Southern Silvicultural Research Conference program & abstracts Virtual: March 16-17, 2021
conference chairs Courtney Siegert John Willis Brady Self hosted by
Mississippi State University USDA Forest Service Southern Research Station
Preface The 21st Biennial Southern Silvicultural Research Conference is being held virtually on March 16-17, 2021. This conference is the latest in a series of meetings designed to provide a forum for the exchange of research information among silviculturist, researchers, and managers. Presentations will emphasize research in artificial and natural hardwood regeneration, fire, intermediate management and stand development, forest measurements and modeling, longleaf pine, shortleaf pine, and vegetation management. The sessions include 67 oral and 24 poster presentations. An online General Technical Report (e-GTR-SRS) will be compiled by the Chairs for publication by the Southern Research Station to document the proceedings. The organizers would like to acknowledge additional sources of support in this year’s virtual meeting. We are grateful to Mississippi State University for developing the conference website, helping with the registration process, and its diligence in handling the fiscal responsibilities of the meeting. We are grateful to Leslie Boby, Darryl Outlaw, and others at Southern Regional Extension Forestry’s Agriculture and Forestry Webinar Portal for serving as the platform host for this meeting. And finally, we are endlessly grateful to Aries Spruell (PhD Student, Department of Instructional Systems and Workforce Development, Mississippi State University) for her technical savvy and support. Thank you, Courtney Siegert, Chair Associate Professor, Mississippi State University John Willis, Co-Chair/Proceedings Editor Research Scientist USDA Forest Service Southern Research Station Brady Self, Proceedings Co-Editor Associate Extension Professor Mississippi State University
Steering committee members include: UNIVERSITIES Courtney Siegert (Chair), Mississippi State University, Starkville, MS Mike Blazier, Louisiana State University AgCenter, Homer, LA Kyle Cunningham, University of Arkansas, Little Rock, AR Tom Dean, Louisiana State University, Baton Rouge, LA Andy Ezell, Emeritus, Mississippi State University, Starkville, MS Gordon Holley, Louisiana Tech University, Ruston, LA Brian Oswald, Stephen F. Austin State University, Nacogdoches, TX Adam Polinko, Mississippi State University, Starkville, MS Michelle Moore, Texas A&M Forest Service, College Station, TX Brady Self (Proceedings Co-Editor), Mississippi State University, Starkville, MS
USDA FOREST SERVICE John Willis (Co-Chair, Proceedings Editor), Southern Research Station, Auburn, AL Don Bragg, Southern Research Station, Monticello, AR Callie Schweitzer, Southern Research Station, Huntsville, AL
INDUSTRY AND ASSOCIATIONS Brian Lockhart, Hardwood Silviculture, LLC, Gentry, AR Mickey Rachel, Roy O Martin Lumber Co., Alexandria, LA David Wilkinson, Hancock Natural Resources Group, Harpersville, AL Buck Vandersteen, LA Forestry Association, Alexandria, LA
21st Biennial Southern Silvicultural Research Conference Schedule
Tuesday, March 16, 2021 9:00 – 10:00 KEYNOTE ADDRESS
A Status Report on Silviculture in the South—Amazing Successes, and the Challenges that Remain. Jim Guldin, Emeritus Scientist, Southern Research Station, USDA Forest Service
10:00 – 12:00 CONCURRENT SESSIONS
SESSION 1: A, B
SESSION 1A – Prescribed Fire 10:00- Mapping functional diversity in a managed 10:15 forest-savanna landscape. // B. Murray, N. Pauley, H. Gholizadeh
10:15- Changes in crude protein concentration of 10:30* understory plants in response to prescribed
fire and thinning. // C. McKinney, R. Masters, A. Adhikari, R. Will, O. Joshi
10:30- Improving bark thickness equations for 10:45* hardwoods in eastern forests. // B. Blood, B. Knapp, D. Dey, G. Wang
10:45- Changes in bark properties and hydrology 11:00 following prescribed fire in temperate forests. // C. Siegert, A. Ilek, A. Wade
11:00- Prescribed fire perspectives of African 11:15 American landowners in Alabama, Florida,
and Georgia. // A. Coates, L. Perkins, K. Hiers
11:15- Litter flammability across southeastern 11:30 tree species: Implications for reversing
mesophication. // M. Varner, J. Kane, J. Kreye, T. Shearman
11:30- Bark morphometry in seven Mississippi tree 11:45 species: pyrophytes, mesophytes, and the implications for post-fire survival. // T. Shearman, M. Varner
11:45- Temporal effects of hurricanes on fuel loading 12:00 and regeneration in the southeastern United States. // L. Pile, S. Guan, B. Song, W. Bridges, G. Wang
SESSION 1B – Bottomland and Riparian Forests 10:00- Occurrence and growth dynamics of natural 10:15* regeneration in an East Texas bottomland
hardwood forest. // L. Rurup, K. Kidd, J. Stovall, B. Oswald, S. Jack
10:15- Evaluating watershed-scale effects of longleaf 10:30 pine restoration on water yield using a paired watershed and modeling approaches. // D. Amatya, D. Hamidi, H. Ssegane, C. Trettin
10:30- Impact of forest land use changes on 10:45 groundwater resources in a basin of Lower
Mississippi River Alluvial Valley over the past 100 years. // Y. Ouyang
10:45- Options for riparian buffer tree planting in 11:00 north Alabama. // C. Schweitzer, D. Dey 11:00- Taxodium distichum survival at the edge of 11:15 the swamp. // S. Moothart, R. Keim 11:15- Assessing the flood tolerance of willows and 11:30* cottonwoods planted in riparian cropland of the Lower Mississippi Alluvial Valley. // T. Kyaw, C. Siegert, H. Renninger, R. Rousseau
11:30- Hardwood diameter growth following partial 11:45 cutting on a minor creek terrace in southeast Louisiana: 17-year results. // B. Lockhart, T. Dean
11:45- Bird response to the clearcut and selection 12:00 regeneration methods in the Mississippi
River batture lands. // B. Lockhart, P. Tappe
Tuesday, March 16, 2021 1:00 – 3:00 CONCURRENT SESSIONS
SESSION 2: A, B
SESSION 2A – Loblolly Pine Management I
SESSION 2B – Natural Disturbances and Climate Change I
Three-year growth and survival of loblolly pine seedlings following various HWC treatments with sulfometuron, imazapyr, hexazinone, and indaziflam. // A. Ezell, A. Self, J. Ezell, J. Belcher
The effect of drought on loblolly pine (Pinus taeda) photosynthesis and whether thinning or genetic entry can improve plantation drought resilience. // N. Cone, J. Adams, M. Blazier, M. Tyree, M. A. Sayer
Glufosinate in site prep tank mixtures for control of natural pines. // A. Ezell, A. Self, J. Ezell
Four year results of a Chopper Gen2 and Forestry Garlon XRT rate and timing study for loblolly pine site preparation on lower coastal plain sites in Georgia. // D. Clabo, D. Dickens
Building forest landowner resilience to hurricane and soil salinization threats in the Southeast U.S. // N. Gibson, S. McNulty, M. Gavazzi, C. Miller, E. Worley, D. Keesee
New understandings of loblolly pine plantations. // D. Zhao
Effects of tornado and salvage harvesting disturbances on vegetative community dynamics in an upland mixed pine - hardwood forest within the Davey Crockett National Forest, Texas. // C. Edwards, A. Blair, S. Shroyer, A. Crowley, K. Kidd
Individual tree diameter growth models for loblolly pine (Pinus taeda). // S. Subedi, K. Poudel, Q. Ma, A. Himes
Suppression of regeneration by Chinese privet (Ligustrum sinense). // T. Turner, T. Dean, J. Kuehny
Tree-size effects on drought-induced mortality vary with species and stand attributes. // L. Zhai
Current and emerging risks to southeast U.S. forests. // K. Bakken, S. McNulty, M. Gavazzi, E. Paradiso, E. Worley
Long-term growth effects of simulateddrought with mid-rotation fertilization and thinning on a loblolly pine plantation in southeastern Oklahoma. // N. Shephard, O. Joshi, C. Meek, R. Will
Control of natural pine using site preparation mixes with Imazapyr, Glyphosate, Saflufenacil, BAS #1, and BAS #2. // A. Self, A. Ezell
First year height performance of planted loblolly pine following site preparation and herbaceous release treatments on a lower coastal plain site. // S. Peairs
Adapting traditional forest management practices to address current and emerging forest threats. // E. Worley, S. McNulty, M. Gavazzi, K. Bakken, E. Paradiso
Will a warmer temperature regime in southern latitudes result in changes in emerald ash borer voltinism and adult emergence phenology? // M. Bataineh, S. Clarke, W. Johnson
Tuesday, March 16, 2021 3:00-5:00 POSTER SESSIONS
SESSION 3: A, B, C, D, E, F
SESSION 3A – Forest Economics 3:003:30
Hedonic analysis of loblolly pine plantation first thinning costs. // E. McConnell
Log length distributions within plantationgrown loblolly pine chip n saw sized trees in southwest Mississippi. // E. McConnell
Probabilistic estimates of costs for treating a southern pine beetle infestation. // C. VanderSchaaf, T. McConnell, M. Crosby, J. Holderieath, J. Meeker, C. Steiner, B. Strom, C. Johson
Projecting stand development and economics of longleaf pine planted outside its native range. // C. VanderSchaaf
SESSION 3C – Forest Soils and the Forest Floor
SESSION 3B – Forest Pests 3:003:30*
Immature emerald ash borer population dynamics and parasitoid effects. // P. Phillips, M. Bataineh
Seasonal light response curves of Ligustrum sinense. // T. Markus, G. Wang
Soil chemical changes following bark beetleinfested wood decomposition. // K. Pace, C. Siegert, J. Tang, N. Clay, R. Hofstetter, O. Leverón, J. Riggins
Tracking the extent and severity of a southern pine beetle outbreak. // M. Crosby, E. McConnell, J. Holderieath, M. Funderburk, J. Meeker, C. Steiner, B. Strom, C. Johnson
SESSION 3D – Measurement and Modeling
Breast level height displacement: do standing trees sink into the soil? // C. VanderSchaaf, B. Zeide, W. Patterson
Ability of site index to differentiate merchantable yield in southern yellow pine plantations. // C. VanderSchaaf
Comparing physicochemical properties and sorption behaviors of pyrolosisderived and microwave-mediated biochar. // C. Brickler, Y. Wu, S. Li, A. Swamy, G. Chen
Developing a simple longleaf pine plantation growth and yield model for the gulf region. // C. VanderSchaaf
Effects of forest canopy cover on splash erosion in upland hardwood forests of Mississippi. W. Kruckeberg, C. Siegert, J. Granger, H. Alexander
Linking canopy cover and standard stand density metrics for Wetland Reserve Easements in Arkansas. // J. Borland, M. Bataineh
Mass loss and nutrient content of hardwood coarse woody debris in the southern Appalachians 21 years after Hurricane Opal. // R. Eaton
Using national inventory data (FIA) to explore the relationship between diversity an productivity in Mississippi forests. // E. Baach, A. Himes
Tuesday, March 16, 2021 3:00-5:00 CONCURRENT SESSIONS CONT.
SESSION 3: A, B, C, D, E, F
SESSION 3E – Natural Disturbances and Climate Change
SESSION 3F – Silviculture and Management
Climate-growth responses among co-occurring upland oak and pine species in East Texas. // S. Shroyer, T. Jones, K. Kidd
A Photographic Record of the First Silvicultural Research of the Southern Forest Experiment Station. // D. Bragg
Experimentally measuring effects of soil moisture on windfirmness in Pinus elliottii using static winching. // S.H. Scully, S. Taylor, C. Peterson, J. Cannon
Effects of post-fire disturbance responses of Microstegium vimineum on native hardwoodseedling regeneration. // Z. Chandler, A. Himes
Growth response of mature longleaf pine to disturbance at the Harrison Experimental Forest. // J. Butnor, R. Eaton, D. Nelson
Longleaf and Lasers: Improving Models for Wind Susceptibility in the Coastal Plain. // C. English, J. Cannon, K. Hiers
Examining initial effects of planting stock differences on growth and survival in an artificially regenerated shortleaf pine restoration in the southern Appalachian Mountains. // A. MacDonald, T. Keyser
Sprouting response of three-year-old planted shortleaf pine one growing season year after prescribed fire in East Texas. // J. Wilkins, K. Kidd, S. Shroyer, B. Oswald, S. Jack
Wednesday, March 17, 2021 9:00-10:00 CONCURRENT SESSIONS
SESSION 4: A, B SESSION 4B – Natural Disturbances and Climate Change II
SESSION 4A – Loblolly Pine Management II 9:009:15
Biography of Russell R. Reynolds, a pioneering Forest Service silviculture researcher. // D. Bragg
A reevaluation of superior tree performance after 48 years for a loblolly pine progeny test in southern Arkansas. // D. Bragg
Crown lifting techniques for maintaining stem quality in widely spaced pine plantations. // D. Collins, J. Granger, S. Dicke, C. Hale
Response duration after a mid-rotation fertilizer application in Pinus taeda. T. Albaugh, D. Carter, C. Cohrs, R. Cook, R. Rubilar, O. Campoe
A stand level application of efficiency analysis to understand efficacy of fertilization and thinning with drought in a loblolly pine plantation. // N. Shephard, A. Susaeta, O. Joshi, C. Meek, R. Will
Effectiveness of commercially available Japanese stilt grass (Microstegium vimineum) control methods. // C. Beam, C. Siegert, J. Granger, R. Iglay
Mapping forest restoration in Lower Mississippi Alluvial Valley. // N. Rai, Q. Ma, J. Yang
Connecting strategic planning with forest operations using the Forest Adaptive Management Online User System (FAMOUS). // E. Paradiso, S. McNulty, M. Gavazzi, K. Bakken, E. Worley
Wednesday, March 17, 2021 10:00-12:00 CONCURRENT SESSIONS
SESSION 5: A, B
SESSION 5A – Longleaf Pine Management 10:00- Can longleaf pine plantations be modeled by 10:15* calibrating mixed-effects models of other species? // C. VanderSchaaf, H. Burkhart, M. A. Sayer
10:15- Survival, growth, carbon isotope 10:30 discrimination and cold tolerance of
wide-ranging provenances of longleaf pine grown in the northern edge of its range. // K. Johnsen, J. Butnor, J. Creighton, C. Maier, P. Schaberg, G. Hawley
10:30- Linkage between longleaf pine seedling 10:45 morphology and emergence from the grass stage. // M. A. Sayer, S. Sung
10:45- 23-Year impacts of bi-annual seasonal 11:00 burning and alternative understory
treatments on longleaf pine productivity. // J. Willis, A. Sharma, J. Kush
11:00- A research prospectus: effects of canopy 11:15* gaps created by Hurricane Michael on
longleaf pine regeneration and community reorganization. // C. Pope, S. Bigelow, A. Sharma, J. Cannon
11:15- Understanding wind risk to forests: Towards 11:30 mechanistic models of wind risk in the southeastern Coastal Plain. // J. Cannon, B. Rutledge, K. McIntyre, A. Holland, S. Jack
11:30- Percentage of trees bearing cones as a 11:45 predictor for annual longleaf-pine cone production. // T. Patterson 11:45- Tree size, stand density, and crown position 12:00 influence a hurricane’s damage to planted
longleaf pines. // S. Bigelow, A. Whelan, J. Cannon, G. Starr, C. Staudhammer, G. Kenney
SESSION 5B – Upland Hardwoods Management I 10:0010:15
Natural pruning varying with sweetgum variety and density. J. Adams, M. Blazier, C. VanderSchaaf
Twenty-eight years of cooperative oak research and technology development in the southern region. // S. Clark, S. Schlarbaum, B. Crane
10:30- Twenty-eight years of cooperative oak 10:45* research and technology development in the southern region. // I. Ojo, L. Ngatia, C. Oishi, J. Grace, A. Lorenzo
Legacy effects of past harvesting on woody understory structure and composition in contemporary deciduous broadleaved forests of the southern Appalachian Mountains. // T. Keyser, J. Rodrigue
Long-term effects of alternative partial harvesting methods on the woody regeneration layer in high-elevation Quercus rubra forests of the southern Appalachian Mountains, USA. // T. Keyser, D. Loftis
Effects of long-term forest management on mercury bioaccumulation in aquatic food webs. // P. Ku, M. Tsui, T. Farmer, D. Amatya, C. Trettin, A. Chow
11:30- Biomass production of eastern cottonwood 11:45* (Populus deltoids Bartr. Ex Marsh) and black
willow (Salix nigra Marsh.) in the Lower Mississippi Alluvial Valley. // B. Dahal, K. Poudel, H. Renninger, J. Granger, T. Leininger, E. Gardiner, R. Souter, C. Sabatia
11:45- Impacts of Microstegium vimineum on 12:00* seedling growth and survival of three
common hardwood species under different light and moisture levels. // C. Goldsmith, H. Alexander, J. Granger, C. Siegert
Wednesday, March 17, 2021 1:00-3:00 CONCURRENT SESSIONS
SESSION 6: A, B
SESSION 6A – Shortleaf Pine Management
SESSION 6B – Upland Hardwoods Management II
Shortleaf pine sprouting and pine competitive status during the first growings eason after prescribed burning in a Mid-Atlantic mixedwood forest. // M. Olson
Preferential herbivory by cottontail rabbits (Syvilagus floridanus) in planted oak seedlings. // S. Madden, H. Renninger, A. Self, A. Ezell, J. Granger
Analyzing 62 year data on shortleaf pine trees in common garden experiment. // G. Gallagher, M. Olson
Intraspecific competition increases growth of enrichment-planted shortleaf pine seedlings in a mixed-hardwood clearcut on a xeric site after 13 years in the southern Appalachians. // H. McNab
Fifth year development of natural regeneration following pre-commercial herbicide release treatments. // S. Peairs, W. Clatterbuck
Restoration of conifers to a xeric oak ridge site by clearcutting and planting shortleaf and pitch pines - lessons learned after 13 years. // H. McNab
Understory invasion by Microstegium vimineum in a closed-canopy oak forest leads to high mortality of white and Shumard oak seedlings. // H. Alexander, C. Goldsmith, J. McDaniel, R. Nation, A. Paulson
Is there hope for hybrid poplars in the southern United States. // K. Smith, R. Rousseau, M. Murphy
Early growth and survival of bareroot loblolly pine (Pinus taeda), bareroot shortleaf pine (Pinus echinata), and containerized shortleaf pine in central Mississippi. // S. Madden, H. Renninger, A. Self, A. Ezell, J. Granger
Water use and efficiency of eastern cottonwood and hybrid poplars grown on contrasting sites in the Southeastern U.S. // H. Renninger, L. Stewart, R. Rousseau
Radial growth response of shortleaf pine (Pinus echinata) and post oak (Quercus stellata) to climatic variability and management in southeastern Oklahoma. // R. Will, A. Adhikari, R. Masters, H. Adams, O. Joshi, C. Zou
Tuesday, March 16, 2021 10:00 – 12:00 CONCURRENT SESSIONS
SESSION 1: A, B
SESSION 1A – Prescribed Fire
Mapping functional diversity in a managed forest-savanna landscape. B. Murray, Assistant Professor, Oklahoma State University, Stillwater, OK
N. Pauley, MS Student, Oklahoma State University, Stillwater, OK H. Gholizadeh, Assistant Professor, Oklahoma State University, Stillwater, OK
Changes in crude protein concentration of understory plants in response to prescribed fire and thinning. C. McKinney, Graduate Student, Oklahoma State University, Stillwater, OK R. Masters, OK A. Adhikari, Postdoctoral researcher, Oklahoma State University, Stillwater, OK R. Will, Professor, Oklahoma State University, Stillwater, OK O. Joshi, Professor, Oklahoma State University, Stillwater, OK
Functional diversity links the resilience of ecological communities with the ecosystem services that communities generate for local economies. With respect to resilience, a community with a greater diversity of traits may be more likely to absorb a pulse disturbance, or slowly adapt to a press disturbance, due to the greater variety of traits. Satellite and aerial remote sensing are promising for continuously mapping the functional diversity of landscapes, and then studying the impact of forest management on functional diversity. In this study, we applied multispectral imagery and airborne LiDAR in mapping vegetation indices and structural diversity in a forest management demonstration area. Vegetation indices included the enhanced vegetation index (EVI), the chlorophyll vegetation index (CVI), and the normalized difference water index (NDWI). Structural traits included canopy height (CH), foliage height diversity (FHD), and total vegetation density (TVD). We determined functional diversity based on the metrics functional richness (FRic), functional evenness (FEve), and functional divergence (FDv) for the vegetation indices and structural traits. Our study area, the Pushmataha Wildlife Management Area in southeast Oklahoma, was composed of oak-pine forest and savanna, and includes a forest research demonstration area managed with prescribed fire and thinning for over 35 years. Among treatments in the demonstration area, we detected differences in functional traits with respect fire return interval, hardwood thinning, and pine harvest. Functional evenness and divergence differed only based on fire return interval. Our study demonstrates how the functional diversity of forested landscapes may be mapped using available data. Prescribed fire and thinning can be used to produce and maintain woodlands and savannas which provide improved wildlife habitat by increasing the productivity of understory vegetation. While the changes in understory composition and productivity with decreasing tree canopy cover are well understood, changes in forage quality are less studied. To understand how forage quality changes among managed ecosystems ranging from closed-canopy shortleaf pine (Pinus echinata) and post oak (Quercus stellata) forest to savanna, we tested the crude protein concentration of 11 species of understory plants. We collected samples at three key times of the year for white-tailed deer (Odocoileus virginianus), early spring when forage quantity is the most limited, mid-summer when deer protein demand is highest, and mid-autumn when forage crude protein is lowest. This research was conducted at Pushmataha Wildlife Management Area in Pushmataha County, Oklahoma where a series of replicated experimental plots established and maintained since 1984 test the effects of four different intervals of prescribed fire and various tree harvesting and thinning regimes. Our results indicate that crude protein concentration was higher in forested areas with longer fire return intervals. Protein concentration also followed predictable annual patterns, but time of year did not interact significantly with ecosystem type. This has management implications for white-tailed deer as nutritional carrying capacity is a function of both forage quantity and quality, and simply focusing on maximum biomass production may come at the cost of lower quality forage.
Improving bark thickness equations for hardwoods in eastern forests. B. Blood, PhD Student, Clemson University, Clemson, SC
B. Knapp, Associate Professor, University of Missouri, Columbia, MO D. Dey, Research Forester, USFS Northern Research Station, Columbia, MO G. Wang, Professor, Clemson University, Clemson, SC
Changes in bark properties and hydrology following prescribed fire in temperate forests. C. Siegert, Associate Professor, Mississippi State University, Mississippi State, MS
A. Ilek, Faculty, Poznan University of Life Sciences, Poznan A. Wade, PhD Student, Mississippi State University, Mississippi State, MS
Prescribed Fire Perspectives of African American Landowners in Alabama, Florida, and Georgia A. Coates, Assistant Professor, Virginia Tech, Blacksburg, VA
L. Perkins, Landscape Conservation Program Coordinator, Defenders of Wildlife, Washington, DC K. Hiers, Wildland Fire Scientist, Tall Timbers Research Station and Land Conservancy, Tallahassee, FL
Recognition of the role of wildland fire in forested ecosystems of the eastern US has increased in recent decades, with greater interest in the use of prescribed fire and several recent high-profile wildfires. Because fire inevitably kills some trees, tree mortality becomes a vital part of forest management. Therefore, accurately predicting tree mortality from fire injury becomes critical to mitigating undesirable fire effects, planning prescribed fire, and understanding fire ecology. The First Order Fire Effects Model (FOFEM) is an empirical model developed to predict tree mortality following fire using bark thickness (derived from tree diameter) and crown scorch estimates. Since bark thickness changes with stem size, FOFEM estimates bark as a species-specific proportion to stem size and assumes bark thickness follows a simple linear relationship across stem sizes. Unfortunately, the accuracy of these bark thickness estimates has not been independently tested. We present results from a project designed to evaluate and refine FOFEM for use in eastern hardwood forests. Modeled probability of tree mortality varies by species and decreases with tree size based on species-specific, linear equations used to predict bark thickness from tree diameter. We develop new bark thickness equations for over fifty common eastern species, accounting for non-linear relationships between bark thickness and tree diameter when appropriate. We have also determined the extent to which geography alters bark growth for ten species. Results from our work will provide accurate estimations of bark thickness, which should improve the prediction of tree mortality associated with fire in eastern forests. In the eastern United States, the use of prescribed fire as a silvicultural technique to manage for desirable upland tree species is increasing in popularity. Bark physical properties such as thickness, density, and porosity have known associations with fire tolerance among species. These physical properties simultaneously influence rainfall interception and canopy storage and thus are of interest across a range of disciplines. Furthermore, while these characteristics are innate to a species, it is unknown whether repeated exposure to fire facilitates physical change in bark structure and whether these changes are consistent among species. To answer these questions, bark samples were collected from mature pine (Pinus taeda) and oak (Quercus montana) trees from sites across the Bankhead National Forest in Alabama, USA under three different burn regimes: 3-year cycle, 9-year cycle, and no fire. Samples were analyzed in the laboratory for bulk density, porosity, water storage capacity, and hygroscopicity (the amount of atmospheric water vapor absorbed by bark during non-rainfall conditions). Drying rates of saturated samples under simulated wetting conditions were also assessed. Oak bark had higher bulk density, lower porosity, and dried slower than pine bark. Interestingly, bark from both species had lower bulk density, higher porosity, greater water storage capacity, and dried faster in stands that were burned every 3 years compared to other fire regimes. Preliminary findings suggest that bark structure does indeed change with repeated exposure to fire leading to increases in water storage capacity and slower evaporation. The attitudes, perspectives, and land management choices of African American, non-industrial, private landowners in the southeastern US are frequently underreported in landowner surveys. As a result, there is a lack of knowledge within this region regarding African American perspectives of prescribed fire. Twenty-one African American, non-industrial, private landowners in Alabama, Florida, and Georgia were interviewed during summer 2019 to develop a better understanding about their knowledge, opinions, and use of prescribed fire. Eighty-one percent of these landowners used prescribe fire on their properties for a variety of management purposes, including: hazardous fuel reduction, undesired vegetation control, timber stand improvement, pest and disease reduction, and aesthetics. Unique potential barriers to prescribed fire use included: 1) a lack of African American representation within management organizations and outreach agencies; 2) inadequate education regarding burn permits, human safety during burning operations, and burn strategies for small parcels; and 3) inadequate access to local training events and prescribed burn associations. Future surveys, educational programs, and outreach events within this region may benefit from evaluating and addressing these unique barriers within agency-related leadership structures and landowner programming.
Litter flammability across southeastern tree species: Implications for reversing mesophication.
M. Varner, Director of Fire Research & Senior Scientist, Tall Timbers Research Station, Tallahassee, FL J. Kane, Associate Professor, Humboldt State University, Arcata, CA J. Kreye, Assistant Professor, Pennsylvania State University, University Park, PA T. Shearman, Post-doctoral Research Scientist, Tall Timbers Research Station, Tallahassee, FL
Bark morphometry in seven Mississippi tree species: pyrophytes, mesophytes, and the implications for post-fire survival.
T. Shearman, Post-doctoral Scientist, Tall Timbers Research Station, Tallahassee, FL M. Varner, Director of Fire Research, Tall Timbers Research Station, Tallahassee, FL
Temporal effects of hurricanes on fuel loading and regeneration in the southeastern United States. L. Pile, Research Ecologist, USDA Forest Service – Northern Research Station, Columbia, MO
S. Guan, Former Graduate Student, Clemson University, Clemson, SC B. Song, Associate Professor, Clemson University, Clemson, SC W. Bridges, Professor, Clemson University, Clemson, SC G. Wang, Professor, Clemson University, Clemson, SC
Widespread fire exclusion and land-use activities across many southeastern forested ecosystems have resulted in altered species composition and structure. These changes in composition and structure have been implicated in positive fire-vegetation feedbacks termed “mesophication” where fire spread and intensity are diminished. In forests and woodlands, inherent flammability of different species is the mechanistic driver of mesophication. To date, there has been limited work on documenting the high diversity of species in the region, limiting the ability to differentiate among species to restore fuels that sustain fire regimes. Here, we coalesce disparate flammability data and add missing species across the spectrum from species that facilitate fire (so called “pyrophytes”) to those that dampen fire (so called “mesophytes”). We present data on 36 species from across the southeast, all burned using identical laboratory methods. The most flammable species burned were a suite of pines (Pinus palustris, P. elliottii, P. serotina, and P. rigida), American chestnut (Castanea dentata), and several oaks (Quercus laevis, Q. falcata, Q. alba, and Q. marilandica). At the mesophytic end, the least flammable species were Tsuga canadensis, P. clausa var. clausa, Acer rubrum, and several other hardwoods implicated in mesophication. These data fill in some key holes in our understanding of southeastern fire adaptations, but also provide context for restoration decisions and fire management prioritization efforts to restore and sustain fire-prone ecosystems. Bark is a complex multifunctional structure of woody plants that varies among species. Thick bark is one of a suite of traits that can enable “pyrophytic” species to survive and grow into the canopy when a surface fire occurs, while thin-barked “mesophytic” species are top-killed. Other bark traits beyond thickness offer potential protection advantages. Bark rugosity, measured as the ratio of total cross-sectional area to its convex hull is a new metric to describe rough bark, where bark is thickest along ridges and thinnest in valleys. Rugose bark can potentially alter heat flow around the bole and prevent leeward vortices from producing standing leeward flames. The objective of this study was to document and compare inner and outer bark allocation and rugosity in tree saplings in seven species (Carya tomentosa, Nyssa sylvatica, Prunus serotina, Pinus echinata, Pinus taeda, Quercus marilandica, and Q. falcata) across a pyrophyte to mesophyte gradient in the Tallahatchie Experimental Forest in north Mississippi. Ten saplings of each species were destructively sampled. Cross-sections were digitally scanned on a flatbed scanner. Total area, outer and inner bark area, and wood area were measured using ImageJ software. The frequency and severity of extreme weather events, including hurricanes, are expected to increase in response to global change. Concurrently, coastal southern US forests, will experience droughts that may facilitate a rise in the occurrence of wildfires. Wind damage can substantially alter fuel dynamics and forest structure in coastal forests by increasing their susceptibility to wildfire, especially during severe drought. To mitigate excessive fuel loading, managers commonly use salvage logging and prescribed fire, and time since disturbance may further reduce fuel loads through decomposition. To understand the effect of hurricanes on fuel loading, and the impact of time since disturbance and management action we compared fuel loads across four hurricanes: Hugo (1989), Opal (1995), Katrina (2005), and Ike (2008). Fuels and regeneration data were collected across five upland pine study sites located in South Carolina, Alabama, Mississippi, and Texas. Highly impacted stands (managed and/or unmanaged) were paired with an equal number of less impacted, control stands at each site. Fuels data were collected using Brown’s planar intercept method and tree regeneration was tallied by species along. Fuel accumulations increased dramatically with disturbance but decreased and stabilized with time. With frequent prescribed fire, coarse woody debris decreased more rapidly than without fire. However, without prescribed fire, damaged stands had greater fuel loads than control stands, even after 24 years. Salvage logging reduced fuel loads across all fuel size classes. Although overstory mortality can provide growing space for regeneration of shade-intolerant species, effects from frequent prescribed fire override resource availability for recruitment. Outer bark was thickest in the oaks and pines, and thinnest in the mesophytic species as well as hickory, which developed thick inner bark, but relatively thin outer bark. Bark rugosity was and was positively correlated to bark thickness. Differentiating inner and outer bark thickness as well as considering bark rugosity may improve our understanding of tree survival and future stand dynamics.
Tuesday, March 16, 2021 10:00 – 12:00 CONCURRENT SESSIONS
SESSION 1: A, B
SESSION 1B – Bottomland and Riparian Forests
Occurrence and growth dynamics of natural regeneration in an East Texas bottomland hardwood forest.
L. Rurup, Graduate Research Assistant, Stephen. F Austin State University, Nacogdoches, TX K. Kidd, Assistant Professor, Stephen. F Austin State University, Nacogdoches, TX J. Stovall, Professor, Stephen. F Austin State University, Nacogdoches, TX B. Oswald, Professor Stephen. F Austin State University, Nacogdoches, TX
Bottomland hardwood forests provide critical services such as water quality improvement, nutrient cycling, flood and erosion control, carbon sequestration, and support of biodiversity. In recent decades, these forests have been negatively impacted by river regulation, altering hydrology and flooding patterns, and the invasion of species such as Chinese tallow. As a result, these forests have experienced declines in productivity and regeneration potentials of desired species. This study quantified density, height, and diameter of established regeneration for three species groups: desired native (e.g., overcup oak, cherrybark oak, willow oak, etc.), less desired native (e.g., American hornbeam, green ash, water hickory, water-elm, American elm, etc.) and invasive (Chinese tallow) along the Neches River in eastern Texas. The influence of abiotic (e.g., microtopography, leaf litter and down woody debris occurrence, light) and biotic (e.g., abundance of Chinese tallow, feral hog damage, ground cover by other growth forms) environments on successful establishment and regeneration was quantified. While all species groups were fairly abundant as small seedlings, Chinese tallow was much more prevalent in the sapling stage than oak and less desired native species. Areas that had been recently been treated for Chinese tallow often had a high density of small Chinese tallow seedlings on the forest floor due to increased light availability. Future management will be necessary to ensure that native desired species will be positioned to be recruited into the overstory as canopy gaps are created.
S. Jack, Founding Executive Director, Boggy Slough Conservation Area, Lufkin, TX
Evaluating watershed-scale effects of longleaf pine restoration on water yield using a paired watershed and modeling approaches. D. Amatya, Research Hydrologist, USDA Forest Service, Southern Research Station, Cordesville, SC
D. Hamidi, PhD Graduate Student, University of Durham, Durham, U.K. H. Ssegane, Principal Data Scientist, Oshkosh Corporation, Oshkosh, WI C. Trettin, Supervisory Research Soil Scientist, USDA Forest Service Southern Research Station, Cordesville, SC
Restoration of longleaf pine (LLP) ecosystems is a public land management objective throughout the southeastern U.S. An accurate understanding of linkage between watershed-scale LLP restoration and hydrological processes is important as issues on regional water resources increase but information on its effects on water yield is lacking. In contrast to loblolly pine stands, LLP stands with a much lower stocking may potentially influence soil moisture and evapotranspiration (ET), for that matter water yield. The objective of this study is to develop a flow calibration relationship of 1st order paired watersheds (155-ha WS77 (treatment) and 160-ha WS80 (control)) using measured rainfall, streamflow, weather, water table, and other parameters in conjunction with MIKESHE hydrologic modeling for 2011-2019 period to test the hypothesis of increased water yield due to decrease in ET after LLP restoration on the Santee Experimental Forest in South Carolina. The monthly streamflow calibration relationship (WS77 = 1.03*WS80 + 7.00; R2 = 0.83; p = 0.0005) was highly significant. The model predicted flow also agreed well with observed flow (R2 = 0.82; NSE = 0.80 for daily and R2 = 0.93; NSE = 0.93 for monthly periods) for the WS77 watershed with the average leaf area index (LAI) of 3.95 for current loblolly dominated stands. We will apply the calibrated model for simulating effects of the LLP restoration scenario, assuming LAI of 2.0 for lower understocking/root depth, on mean annual water yield by using future climatic data from multiple climate change models for this specific region to assess prediction uncertainties.
Impact of forest land use changes on groundwater resources in a basin of Lower Mississippi River Alluvial Valley over the past 100 years. Y. Ouyang, Research Hydrologist, USDA Forest Service, Mississippi State, MS
Options for riparian buffer tree planting in north Alabama. C. Schweitzer, Research Forester, USDA Forest Service- Southern Research Station, Huntsville, AL
D. Dey, Research Forester and Project Leader, USDA Forest ServiceNorthern Research Station Columbia, MO
Taxodium distichum survival at the edge of the swamp. S. Moothart, Masters Graduate, Louisiana State University, Monument, OR
R. Keim, Professor, Louisiana State University, Baton Rouge, LA
Groundwater overdraft, resulted from anthropogenic activities, is an issue of critical concern. Many regions of the world are now facing challenges on the decline and/or shortage of groundwater resources. This also is occurring in the Lower Mississippi River Alluvial Valley (LMRAV), which is a key region for crop and forest productions in Midsouth USA. Although forest lands have been recognized for conserving water resource, improving water quality and mitigating river flood, the impacts of silvicultural managements on groundwater resources in the LMRAV are poorly understood. Using the historical data of forest reduction, recorded precipitation, and groundwater recharge along with the US Geological Survey’s MERAS (Mississippi Embayment Regional Aquifer Study) groundwater model, we assess the impacts of forest land use changes over the past 114 years (from 1900 to 2014) on groundwater resources in the Yazoo River basin, which is within the LMRAV and is a largest river basin in Mississippi. The specific objectives are to: (1) determine the century-long correlation between forest clearcutting and groundwater recharge; (2) simulate the temporal and spatial distributions of groundwater level due to the past deforestation; and (3) ascertain the long-term contribution of forest lands to groundwater resource. Results from this study will be presented and discussed. Knowledge gained from this historical study will provide very useful information to the local and regional foresters and water resource managers in planning groundwater supply strategies. Degradation of riparian zones due to farming and livestock grazing are considered major contributors to non-point source sediment input into streams. We worked with private, state and federal agencies to examine one approach of habitat restoration of degraded riparian zones along active agriculture fields in northern Alabama. We wanted to determine which species of high-value timber species would grow exceptionally well using artificial regeneration (planting) and semi-intensive silviculture (tending activities for competition). We also examined sediment transport from each block of species to ascertain which provided the highest level of protection to minimize non-point source pollution. We planted 8 species, including black walnut (Juglans nigra), yellow-poplar (Liriodendron tulipfera), green ash (Fraxinus pennsylvanica), sweetgum (Liquidambar styraciflua), Shumard oak (Quercus shumardii), Nuttall oak (Q. nuttallii), cherrybark oak (Q. pagoda) and loblolly pine (Pinus taeda) at two locations. A sediment barrier was used to capture sediment movement off each tree species planting block. After ten growing seasons, survival averaged 78 percent. Loblolly pine was the tallest (34.1 feet) and had the greatest diameter (7.4 inches), followed by green ash. Black walnut had the lowest survival and growth. Over a five-year period, we collected the least sediment (by weight) coming from the green ash blocks during the highest precipitation month of December. Ecological processes controlling transition areas of coastal wetlands between marshes (not forested) and swamps (forested) are poorly understood, despite important ecosystem services provided and strong interest in managing for ecosystem structure and function. The objective of this work was to identify how soil chemistry controls individual-tree growth of the important coastal species baldcypress (Taxodium distichum (L.) Rich.) and pondcypress (var. imbricarium (Nutt.) Croom) along a coastal salinity gradient. Tree cores, soil samples, and stand density measurements were collected for sixty cypress trees at the coastal Joyce Wildlife Management Area, Louisiana, which is a former forested wetland that partially transitioned to marsh following salt-water intrusion in the 20th century. A principal component analysis of tree rings indicated that the trees living in higher salinity were proportionally less responsive to high salinity (drought) years as compared to trees further inland. Thus, trees on the forest-marsh edge, which experience the most seawater influence, apparently have some mechanism to compensate for or avoid higher salinity. The most likely explanation is that microhabitats such as hummocks might be critical for tree persistence in marginal sites such as this.
Assessing the flood tolerance of willows and cottonwoods planted in riparian cropland of the Lower Mississippi Alluvial Valley.
T. Kyaw, PhD Student/Graduate Research Assistant, Department of Forestry, Mississippi State University, Starkville, MS C. Siegert, Associate Professor, Department of Forestry, Mississippi State University, Starkville, MS H. Renninger, Assistant Professor, Department of Forestry, Mississippi State University, Starkville, MS
The floodplain of Lower Mississippi Alluvial Valley (LMAV) has seasonally-inundated marginal lands, which are not favorable for commercial agriculture. Alternatively, planting short rotation woody crops (SRWCs) can be possible for biomass production in marginal areas but research is necessary to examine site suitability of SRWCs. A field trial was established in Sidon, MS in June 2018. The plantation contained 4 replicated blocks in an elevational gradient from an oxbow of the Yazoo River, and each of which had 75 cuttings of Eastern cottonwood (Populus deltoides) and black willow (Salix nigra). By chance, the study site experienced abnormally wet conditions into the growing season during the first two years of growth, providing an opportunity to understand tolerance to flooding depth and duration. To monitor water level and temperature, groundwater wells with water level sensors were installed throughout the plots. Results indicated that groundwater levels were 1.2 m below the surface in 2018 and 1.0 m in 2019; and the floods peaked at 1.2 m in 2018 and 3.8 m in 2019. Almost no trees survived in the blocks that were underwater from December 2018 to August 2019 with deeper floodwater (3.8 m). Only trees under shorter duration of floods (January to June 2019) and less deep water (3.5 m in willows and 2.9 m in cottonwoods) survived. Therefore, despite extreme floods in 2019, SRWCs could tolerate a consecutive six-month inundation.
R. Rousseau, Extension/Research Professor, Mississippi State University, Starkville, MS
Hardwood diameter growth following partial cutting on a minor creek terrace in southeast Louisiana: 17year results. B. Lockhart, Owner, Hardwood Silviculture, LLC, Gentry, AR
T. Dean, Professor, School of Renewable Natural Resources, Louisiana State University, Baton Rouge, LA
Bird response to the clearcut and selection regeneration methods in the Mississippi River batture lands.
B. Lockhart, Owner, Hardwood Silviculture, LLC, Gentry, AR P. Tappe, Dean, School of Forestry, Agriculture and Natural Resources, Monticello, AR
Terraces are transition zones between active floodplains and uplands. Soils on terraces are older than active floodplains with more pronounced profile development, including inherent pans. Such sites are often converted to other uses, especially pine plantations. The objectives of this study, implemented in a minor creek terrace in southeast Louisiana, were to describe changes in stand composition and structure following partial cutting for three different management objectives: (1) maximize timber production, (2) maximize wildlife habitat, and (3) to improve timber production and wildlife habitat. Stand composition prior to harvesting was heavy to oak compared to sweetgum and pine. Greater diameter growth occurred in treated plots compared to non-harvested controls plots six year after harvesting. We will present results 17 after harvesting.
The Mississippi River batture is land that is located between the river and adjacent levees. These sites are subject to unnatural flooding events (longer duration and deeper depths) due to constrictions by the mainline levee system. With these conditions in mind, we initiated a large-scale study on Pittman Island, Issaquena County, Mississippi. Two regeneration methods, clearcut and selection, were implemented on 50-acre plots and, along with an unharvested control, were replicated three times for a 450-acre study site. One aspect of this study involved the response of birds to these treatments. Pre-treatment bird surveys conducted in July 1995 recorded 879 individuals from 37 difference species. The most recorded species included the northern cardinal (Cardinalis cardinalis; 13.5%), Acadian flycatcher (Melanerpes carolinus; 9.0%) and red-bellied woodpecker (Melanerpes carolinus; 9.0%). Seventeen species were classified as neotropical migrants while the other 20 species were classified as residents. In addition to total individuals we will present species diversity, richness, and evenness for 1995 and four successive years post-harvest.
Tuesday, March 16, 2021 1:00 – 3:00 CONCURRENT SESSIONS
SESSION 2: A, B
SESSION 2A – Loblolly Pine Management I
Three-year growth and survival of loblolly pine seedlings following various HWC treatments with sulfometuron, imazapyr, hexazinone, and indaziflam. A. Ezell, Switzer Distinguished Professor Emeritus and Department Head Emeritus, Mississippi State University, Starkville, MS
A total of 10 herbaceous weed control (HWC) treatments were evaluated on recently planted 1-0, bareroot loblolly pine seedlings. Three replications of each treatment were installed in February, 2018 on a site owned by Weyerhaeuser in northeastern Mississippi. Initial height and groundline diameter (GLD) were recorded prior to treatment application. Survival, height, and GLD were recorded in October of 2018, 2019, and 2020. Results from the third year measurements will be presented. Survival was very good to excellent in all treatments. All herbicide treatments resulted in significantly greater growth as compared to the untreated control plots, but significant differences were also noted among the herbicide treatments.
A. Self, Associate Extension Professor, Mississippi State University, Grenada, MS J. Ezell, Lecturer, Mississippi State University, Starkville, MS J. Belcher, Stewardship and Development Manager-Eastern U.S., Bayer Cropscience, Auburn, AL
Glufosinate in site prep tank mixtures for control of natural pines. A. Ezell, Switzer Distinguished Professor Emeritus and Department Head Emeritus, Mississippi State University, Starkville, MS A. Self, Associate Extension Professor, Mississippi State University, Grenada, MS J. Ezell, Lecturer, Mississippi State University, Starkville, MS
With the recent concerns over the use of glyphosate, some forest managers are seeking a replacement for use in site preparation applications. Of particular interest is the control of natural pines in areas to be planted with genetically improved pine seedlings. A pilot study was installed to evaluate the efficacy of substituting glufosinate for glyphosate in site prep tank mixtures. The study area had established natural loblolly pines which were 1-9 feet tall with the majority of the pines being 1-3 feet tall. The four treatments were applied at two timings (July and October, 2019) with three replications at each timing. All stems of woody species in treatment plots were recorded by species and height class prior to treatment application. Living pines were recorded again in March, 2020. Results for post-treatment brownout response and pine control will be presented.
Four year results of a Chopper Gen2 and Forestry Garlon XRT rate and timing study for loblolly pine site preparation on lower coastal plain sites in Georgia D. Clabo, Assistant Professor of Silviculture Outreach, University of Georgia Warnell School of Forestry & Natural Resources, Tifton, GA
D. Dickens, Professor of Forest Productivity, University of Georgia Warnell School of Forestry & Natural Resources, Statesboro, GA
New understandings of loblolly pine plantations.
D. Zhao, Senior Research Scientist, Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA
Chopper® Gen2TM (2 lb. acid equivalent imazapyr-BASF) and Forestry Garlon® XRT (6 lb. acid equivalent ester triclopyr-Corteva® Agriscience) are commonly used herbicides for site preparation in the southeastern United States. When used together, these herbicides offer broad spectrum control of many hardwood tree and shrub species including difficult to control waxy leaf species such as gallberry, titi, waxmyrtle, etc. Limited research results are available concerning different tank mix application rates and timings for Coastal Plain sites. The objectives of this study were to investigate the impacts of Chopper® Gen2TM and Forestry Garlon® XRT applied in combination at two rates as well as each herbicide applied alone on the survival and growth of planted loblolly pine. In addition, the effects of three herbicide application timings (late July, mid-September and late October) on planted loblolly pine survival and growth were investigated. Two study sites (one poorly and one well drained) were established in Effingham County, Georgia. Site one (Egypt) received a split-plot herbaceous weed control (HWC) treatment post-planting, while the second site (Springfield) did not receive HWC. Four year results indicated that all site preparation herbicide treatments resulted in greater survival and growth than the control treatment, while diameter and volume index often was greater following September applications. Herbaceous weed control at the Egypt site significantly improved loblolly pine growth and survival to a lesser degree. As these stands age, additional measurements are needed to determine if a certain herbicide and application timing combination is superior on Lower Coastal Plain sites. Pine plantations in the southern US have been among the most intensively managed forests in the world. Their productivity has been enhanced by intensive silvicultural treatments over the past 60 years, and our knowledge about their treatment response has been expanded through long-term large-scale experimental studies. The analysis of nine long-term loblolly pine field trials resulted in several new findings. For loblolly pine in the southern US, there exist maximum productivity and maximum response to silvicultural practices. The maximum response was inversely proportional to the base site quality, and silvicultural treatments never increased productivity above that maximum. The maximum stand BA and maximum SDI were redefined for individual stands. The average maximum stand BA and maximum SDI were 46.2 m2 ha-1 and 1002 tph, respectively, and both showed significant variation (30.2 ± 61.7 m2 ha-1 and 600 ± 1410 tph, respectively). Stand aboveground net primary production (ANPP) generally increased with increasing site quality, due to increased stand foliage biomass in the early stage of stand development, and mainly due to increased growth efficiency in the late stages of stand development. More intensive cultural treatments increased foliage biomass, thus increased ANPP at early ages; thereafter cultural intensity did not affect foliage biomass, ANPP, and growth efficiency. The trend of early age increases in both foliage biomass and ANPP resulting from increased planting density did not hold true with stand development.
Individual tree diameter growth models for loblolly pine (Pinus taeda). S. Subedi, Graduate Research Assistant, Department of Forestry, Mississippi State University, Starkville, MS
K. Poudel, Assistant Professor, Department of Forestry, Mississippi State University, Starkville, MS Q. Ma, Assistant Professor, Department of Forestry, Mississippi State University, Starkville, MS A. Himes, Assistant Professor, Department of Forestry, Mississippi State University, Starkville, MS
Long-term growth effects of simulated-drought with mid-rotation fertilization and thinning on a loblolly pine plantation in southeastern Oklahoma.
N. Shepard, Graduate Research Assistant, Oklahoma State University, Stillwater, OK O. Joshi, Assistant Professor, Oklahoma State University, Stillwater, OK C. Meek, Assistant Superintendent of the Kiamichi Research Station, Oklahoma State University, Stillwater, OK R. Will, Professor, Oklahoma State university, Stillwater, OK
Control of natural pine using site preparation mixes with Imazapyr, Glyphosate, Saflufenacil, BAS #1, and BAS #2 A. Self, Associate Extension Professor, Mississippi State University Extension, Grenada, MS A. Ezell, Professor Emeritus, Mississippi State University, Starkville, MS
The forests in southern United States are defined by the large variation in species composition, stand structure, and site quality. This heterogeneous forest condition can be traced through several centuries of continuous land use change and a variety of harvesting practices. Individual-tree models are well suited for predicting growth under these diverse conditions and are crucial for large scale resource projection and economic analysis of multiple management alternatives. The Forest Inventory and Analysis (FIA) Program of the U.S. Forest Service provides critical status and trend information to resource managers, policy makers, investors, and the public through a system of annual resource inventory that covers both public and private forest lands across the United States. The Southern Research Station has developed an annual inventory system featuring a hexagonal grid of FIA plots to be measured in 5-year inventory cycles, with 20% of the plots measured each year. Using repeated measurement data from the FIA plots, alternative model formulations and fitting techniques for obtaining individual tree annual diameter growth of loblolly pine (Pinus taeda) were tested. Error produced by the methods developed in this study are compared with the error produced by the models currently being used in the Southern United States. Output of this study will be incorporated in the tools being developed for estimating resource inventory by fusing ground-based measurement, remotely sensed data, and future projections of climate.
Loblolly pine (Pinus taeda L.) is the most productive commercial softwood species in the continental USA. Plantation silviculture will face novel productivity challenges due to climate change-induced drought. We examined the effects of 30% throughfall reduction (drought), fertilization, and thinning on a loblolly pine plantation in southeastern Oklahoma, USA to understand how nutrient availability and stand density interact with drier conditions to affect productivity and canopy dynamics. Our treatments were applied at mid-rotation: throughfall reduction age 5 to 13, fertilizer age 5 and 10, and thinning age 10. Drought treatment decreased tree height by 18% during dry periods. Fertilization increased tree diameter by 9%. Thinning increased tree diameter by 5%. Overall, fertilization (+8% standing volume) and simulated-drought (-7% standing volume) counter balanced each other at age 12 and thinning did not interact with either treatment. Positive fertilization effects were supported by increased foliar nitrogen (N) and phosphorus (P) following fertilization, along with increased leaf area index (LAI; +14%) in fertilized plots and intercepted radiation (+5%) in fertilized-thinned plots at age 12. Drought-induced plots demonstrated 11% greater growth efficiency at age 12. Trees under drought treatment had 10% greater basal area growth during wet growing seasons, suggesting droughted trees may exhibit compensatory (recovery) growth after meteorological drought subsides. We show that management and possible post-drought recovery indicates continued plantation viability in southeastern Oklahoma under drier climate scenarios.
Control of natural pine continues to be problematic in forestry site preparation efforts. Thirteen treatments were used in a study testing efficacy of two numbered BASF products (BAS #1 and BAS #2) for natural pine control in combinations with imazapyr and glyphosate. This study was established on a cutover forestry site in northeast Mississippi on August 31, 2018. Natural pine and hardwood stems were recorded prior to treatment applications and again at 14DAT, 56DAT, 90DAT, and 1YR. Results clearly indicate that addition of glyphosate is necessary for adequate control of natural pines and BAS 850H or BAS 851H serve to enhance glyphosate efficacy. In addition, neither BAS #1or BAS #2 provided satisfactory levels of natural pine control in stand-alone treatments.
First year height performance of planted loblolly pine following site preparation and herbaceous release treatments on a lower coastal plain site. S. Peairs, Assistant ProfessorExtension Specialist for Forest management, Clemson Extension Service, Clemson, SC
Chemical applications for site preparation and herbaceous release are critical for establishing stands of loblolly pine in the southeastern United States. Sandy soils commonly found in lower Coastal Plain sites have lower herbicide application rates compared to other soil types but experience reduced length of competition control. This study examines the necessity for conducting both treatments as opposed to single applications of site preparation or herbaceous release only on lower Coastal Plain sites. An incomplete block design was utilized to evaluate five treatments: Two individual site preparation treatments utilizing either1) glyphosate + triclopyr or 2) imazapyr + triclopyr + glyphosate + metsulfuron methyl, a herbaceous release treatments using a high application rates of hexazinone + sulfometuron methyl, and a combination of the second site preparation treatment above plus a lower application rate of herbaceous release. A clearcut harvest occurred in 2018; site preparation treatments were applied in early fall of 2019; and the herbaceous release treatments were applied during May 2020. Vegetation on these sites was well-established after a full growing season following clearcutting.
Tuesday, March 16, 2021 1:00 – 3:00 CONCURRENT SESSIONS
SESSION 2: A, B
SESSION 2B – Natural Disturbances and Climate Change I
The effect of drought on loblolly pine (Pinus taeda) photosynthesis and whether thinning or genetic entry can improve plantation drought resilience.
N. Cone, Graduate Research Assistant, Louisiana Tech University, Ruston, LA J. Adams, Interim Director and Associate Professor, Louisiana Tech University, Ruston, LA M. Blazier, Louisiana State University Hill Farm Research Station, Homer, LA M. Tyree, Associate Professor, Indiana University of Pennsylvania, Indiana, PA M. Sayer, Plant Physiologist, USDA Forest Service Southern Research Station, Pineville, LA
The Southeastern US is known as the “Wood Basket” for producing the vast majority of timber in the country, but projected increases in severe drought events could threaten timber plantations. Loblolly pine (Pinus taeda) is the principle timber species of the southeast and is distributed across the Atlantic and Gulf coastal plains and west into Texas. Western Gulf states (LA, TX, AR, and OK) lie at the edge of the range for loblolly pine and are particularly vulnerable to any changes in precipitation and temperature. Current research suggests two main methods to increase plantation drought resilience: plant drought resistant seedlings or manage tree densities. Through a factorial design we tested the effects of drought and thinning on loblolly pine photosynthesis. We also used three loblolly pine genotypes which represent seed sources from the western and eastern portions of the species distribution. Drought was simulated by building water exclusion shelters around plot perimeters to block vertical water flow and lining perimeters with plastic sheets to stop lateral water flow. Our results suggest that there are genotypic differences in drought sensitivity, and that density reductions may be an effective method to reduce drought stress. Currently eastern seed sources are preferred to maximize plantation productivity, but local western seed sources may improve plantations yields if drought resistance becomes more important in the future.
Building forest landowner resilience to hurricane and soil salinization threats in the Southeast U.S.
N. Gibson, Research Scientist, USDA Forest Service/SRS/EFETAC/SE Climate Hub, RTP, NC S. McNulty, Director/Research Ecologist, USDA Forest Service/SRS/ EFETAC/SE Climate Hub, RTP, NC M. Gavazzi, Coordinator/Natural Resources Specialist, USDA Forest Service/SRS/EFETAC/SE Climate Hub, RTP, NC C. Miller, Manager/Plant Specialist, NRCS Cape May Plant Materials Center, Cape May Court House, NJ
Hurricanes cause billions of dollars in damage each year, and the risk from hurricanes is projected to increase. Hurricanes negatively impact forests through wind damage, flooding, and storm surge, causing reduced tree growth, mortality, and carbon loss. Storm surge can cause soil salinization when saltwater inundates coastal stands and infiltrates into the soil. Sea level rise associated with climate change also contributes to soil salinization in coastal areas through saltwater intrusion and rising groundwater levels. Forest yield decreases as soil salinity increases. Soil salinity is often measured as electrical conductivity, and levels of 8 - 16 dS m-1 render forest stands economically inviable. Foresters need a resource to guide forest management due to increased soil salinity, but available resources are hard to find or inconsistent across localities. Therefore, the USDA SE Climate Hub developed hurricane and salinization guides to help producers prepare for, recover from, and adapt to these threats. The pine forest landowner hurricane guide provides state-specific recommendations for building resilience to, preparing for, and recovering from hurricanes. The regional salinization guide provides recommendations for the landowner to assess the stage of soil salinization in their forest stand. Mitigation options are suggested in the early stages of salinization, and adaptation options are described in each stage. Both guides aim to ameliorate issues caused by climate change, and their applications will be discussed.
E. Worley, Research Assistant, USDA Forest Service/SRS/EFETAC/SE Climate Hub, RTP, NC D. Keesee, State Wetlands Specialist, NRCS Texas, Temple, TX
Effects of tornado and salvage harvesting disturbances on vegetative community dynamics in an upland mixed pine hardwood forest within the Davey Crockett National Forest, Texas. C. Edwards, Graduate Student, Stephen F. Austin State University, Nacogdoches, TX A. Blair, Research Technician, U.S. Forest Service, Kennard, TX S. Shroyer, Student, Stephen F. Austin State University, Nacogdoches, TX A. Crowley, Student, Stephen F. Austin State University, Nacogdoches, TX K. Kidd, Assistant Professor, Stephen F. Austin State University, Nacogdoches, TX
Natural disturbances have the potential to alter forest successional and developmental patterns. Understanding the effects of catastrophic disturbances and the early stages of natural forest recovery could aid in a better understanding of needed potential management intervention. We examined vegetative community structure and composition 18 months following EF2 and EF3 tornado (April, 2019) and salvage operations (completed July 2019 to June, 2020). A total of 25 plots were located across undisturbed reference, tornado damaged without salvage, and tornado damaged with salvage areas. Multivariate analysis indicated distinct differences within the vegetative communities across the disturbance groups. Unharvested tornado disturbed areas had the greatest diversity of saplings while tornado disturbed and salvaged areas had the greatest diversity of herbaceous vegetation with the greatest occurrence of invasive species. These large scale disturbances reset forest successional stages back to stand initiation. By adjusting salvage operations and retaining patches of unharvested areas, the promotion of a diverse and complex forest structure and community could be obtained. These patches will also aid in reducing entry into the stand helping reduce initiation of invasive species that dominate recently disturbed sites.
Suppression of regeneration by Chinese privet (Ligustrum sinense).
T. Turner, Graduate Research Assistant, Louisiana State University, Baton Rouge, LA T. Dean, Professor, Louisiana State University, Baton Rouge, LA J. Kuehny, Director, LSU AgCenter Botanic Gardens, Baton Rouge, LA
Tree-size effects on drought-induced mortality vary with species and stand attributes. L. Zhai, Assistant Professor, Oklahoma State University, Stillwater, OK
Current and emerging risks to southeast U.S. forests.
K. Bakken, Research Scientist, USDA Forest Service/SRS/EFETAC/SE Climate Hub, Raleigh, NC S. McNulty, Director/Research Ecologist, USDA Forest Service/SRS/ EFETAC/SE Climate Hub, Raleigh, NC M. Gavazzi, Coordinator/Natural Resource Specialist, USDA Forest Service/SRS/EFETAC/SE Climate Hub, Raleigh, NC E. Paradiso, Research Assistant, USDA Forest Service/SRS/EFETAC/ SE Climate Hub, Raleigh, NC E. Worley, Research Assistant, USDA Forest Service/SRS/EFETAC/SE Climate Hub, Raleigh, NC
Native hardwood regeneration in the southeast United States is hindered by repeat disturbance events and the presence of invasive species. This study in Baton Rouge, LA aimed to determine the ability of native species in an unkempt urban forest to persist following high winds from hurricane Gustav in 2008 and subsequent salvage logging. In 2009, researchers estimated the density and composition of the regeneration and overstory trees as well as percent crown cover of invasive Chinese privet (Ligustrum sinense) over 45 plots (40.5 m2 each). Percent Chinese privet cover was noticeably high, leading researchers to believe it may be inhibiting native establishment. Ten years later in 2019, researchers returned to the plots to take repeat measurements. Forest composition remains the same and privet crown cover remains high. There has been no increase in regenerating individuals and overstory trees per hectare has significantly decreased while basal area remains the same. These results confirm that the heavy Chinese privet presence is persistent long term and continues to inhibit reproduction of overstory tree species. Tree size is one of the critical considerations in forest management due to its impacts on ecosystem services and disturbance responses. As a widely occurring disturbance, drought caused a large number of tree mortality. The mortality is found to be related to tree size, but this relation is not consistent in previous studies. To identify confounding factors on the size-mortality relation, this study compared the relation across different tree species and stand attributes based on the FIA data of Oklahoma, where there was a severe drought from 2011 to 2014. The results showed that: (1) the tree mortality was 4% in 2010 and reached 14% in 2014, the last drought year; (2) the small trees (< 5 in.) had the highest mortality during the drought, but the medium (5-10 in.) and large trees ( >10 in.) showed faster increases in tree mortality with drought; (3) the high mortality of small trees was more significant in the drought-avoiding species than tolerating ones; (4) the high mortality of small trees was more significant in the stands with higher density and lower species richness. These results suggested that the non-consistent results of size-mortality relation arise from the effects of species and stand attributes. Furthermore, different species composition and stand attributes could be taken into account in forest management to mitigate the drought-induced mortality of trees with different sizes. Forest productivity and health in the southeast US are negatively affected by wildfire, drought, insects, and other threats expected to increase in severity and frequency under a changing climate. Many traditional forest management practices fail to sufficiently address these threats, so adapting management to address these threats is vital in ensuring healthy, productive forests. Forest managers need practical tools that enable climate-informed decision-making to increase forest resilience and reduce risk. Therefore, the Southeast Climate Hub is assessing current and emerging risks and adaptation practices to southeast forests. The forest impacts and management options will then be incorporated into a user-friendly tool for forest land management implementation at the private, state, and federal levels. This presentation will focus on the current and mid-term (i.e., 20 - 50 year) southeast forest stresses by the southeast ecoregion.
Adapting traditional forest management practices to address current and emerging forest threats. E. Worley, Research Assistant, USDA Forest Service/SRS/EFETAC/ SE Climate Hub, Research Triangle Park, NC
S. McNulty, Director/Research Ecologist, USDA Forest Service/SRS/ EFETAC/SE Climate Hub, Research Triangle Park, NC M. Gavazzi, Coordinator/Natural Resource Specialist, USDA Forest Service/SRS/EFETAC/SE Climate Hub, Research Triangle Park, NC K. Bakken, Research Scientist, USDA Forest Service/SRS/EFETAC/ SE Climate Hub, Research Triangle Park, NC
Forest land managers face the difficult challenge of implementing management strategies to reduce wildfires, storms, invasive species, and other threats under a changing climate. Information to manage and adapt to these stressors must be readily available for forests to remain resilient and productive. To enable forest planning based on the best available climate change science, the USDA Forest Service, Eastern Forest Environmental Threat Assessment Center developed the Template for Assessing Climate Change Impacts and Management Options (TACCIMO). Designed for the National Forest System in 2011 and used on state and private lands, TACCIMO is a web-based information delivery tool that connects forest management and planning with peer-reviewed literature to allow for informed decision-making. While useful as a strategic tool, TACCIMO is limited to only providing a forecast of expected outcomes but does not connect those outcomes with operational guidance. Therefore, the Forest Operations Resource Tool (FORT) was developed to consolidate and create a compendium of strategic, site-specific management options that can then be implemented by forest land managers to mitigate threats and risks at the stand-level. Management practices were gathered from historical and widely used literature sources such as the Forestry Handbook, Service Forester’s Handbook. They also specify when and how to implement these practices best. While not a stand-alone tool, FORT will connect with findings from TACCIMO to form an online interface used to generate site-specific adaptive management prescriptions.
E. Paradiso, Research Assistant, USDA Forest Service/SRS/EFETAC/ SE Climate Hub, Research Triangle Park, NC
Will a warmer temperature regime in southern latitudes result in changes in emerald ash borer voltinism and adult emergence phenology? M. Bataineh, Assocaite Professor, University of Arkansas at Monticello, Monticello, AR S. Clarke, Forest Entomologist, USDA-Forest Service-Forest Health Protection, Lufkin, TX W. Johnson, Entomologist, USDAForest Service-Forest Health Protection, Pineville, LA
The emerald ash borer, Agrilus planipennis (EAB), a non-native invasive insect, was confirmed in Arkansas in 2014 and in Louisiana in 2015. Range expansion into the Southern US could influence population demographics, as EAB may have earlier adult emergence and extended periods of activity in warmer temperatures. It has also been assumed that cold, long winters are a requirement for diapause and completion of its life cycle. Consequently, this led to speculations that EAB could either have two generations a year or may not be able to survive in southerly climates. We hypothesized that warmer temperatures would result in accelerated larval development and earlier emergence onset, and that an extended duration of adult emergence would shift the EAB life cycle from univoltine or semivoltine to bivoltine. In our studies, warmer temperatures appeared to accelerate larval development, with 46% of larvae reaching J-larvae stage as early as June, less than 10 weeks from earliest adult emergence and egg hatching dates. Onset of adult emergence coincided with 319-333 cumulative degree days, base 10°C, which is 1-3 weeks after the threshold currently used in trap deployment. Adult emergence period did not appear to be affected by warmer temperature regimes and there was no evidence of a shift from univoltine to a bivoltine cycle. A growing degree day adult phenology model was developed for use in southern latitudes to identify times to safely transport ash products and to optimize the timing for insecticide application and parasitoid releases.
Tuesday, March 16, 2021 3:00-5:00 POSTER SESSIONS
SESSION 3: A, B, C, D, E, F
SESSION 3A – Forest Economics
Hedonic analysis of loblolly pine plantation first thinning costs. E. McConnell, Assistant Professor, Mississippi State University, Mississippi State, MS
Log length distributions within plantation-grown loblolly pine Chip n Saw sized trees in southwest Mississippi
E. McConnell, Assistant Professor, Mississippi State University, Mississippi State, MS S. Tanger, Assistant Professor, Mississippi State University, Biloxi, MS
Hedonic modeling examined harvest systems costs for loblolly pine plantation first thinnings. Variables studied were tract size (50, 100, 250, 500, and 1,000 acres), site index (60, 65, 70, 75, and 80 feet at 25 years), and trees per acre at establishment (485, 585, and 685). The Cutover Loblolly Growth and Yield Model provided thinning yield data for site index and trees planted per acre combinations when stand basal area reached 110 ft2/acre. The harvest system consisted of two rubber-tired feller bunchers, two grapple skidders, and two trailer-mounted loaders. Trucking costs were $4.05/ton across all treatment combinations. Variable stand ages at thinning required converting costs at each factor/ level combination to equivalent annual costs (EAC), $/ton/year, for analysis. The system’s alternative rate of return was set at 10% based on historical logging rate data for Louisiana and Mississippi. Logged EAC was modeled as a function of site index, which produced the greater positive influence (t = 7.3236, p < 0.0001), followed by trees per acre at establishment (t = 6.8556, p < 0.0001), and logged tract size, which produced the only negative effect (t = -21.5119, p < 0.0001). The cost implicitly associated with each independent variable was calculated from the predicted EAC when holding all predictors at their mean levels, which was $2.88/ton/year. Each 10-foot increment of site index added $0.22 to system EAC. Planting 10 additional trees at stand establishment increased system EAC $0.02. Conversely, EAC was reduced ($0.69) for each additional 10 acres of tract size. Chip n Saw (CNS) is an intermediate southern pine timber product, which ranges from 9.0 to 12.0 inches in diameter a breast height (DBH). Market share for CNS is growing in the South, as is the need to better understand trees occupying this product’s size range. An exploratory study of log length distributions within the most recent five years of US Forest Service FIA plot data for the southwest Mississippi unit was conducted. Plots were filtered to provide loblolly pine plantations with stand ages from 26 to 35 years. Published equations were applied to calculate merchantable heights at 6.0-inch diameter outside bark. Inverse regression then estimated log-end diameters at any height along the stems. Log lengths determined were 8, 10, 12, 14, and 16 feet, plus 0.5 feet trim. Loblolly pine trees meeting the CNS size requirement were n = 2,408; n = 979 9-inch, n = 721 10-inch, n = 438 11-inch, and n = 270 12-inch trees occupied each DBH class. An average CNS tree contained two merchantable logs. Collectively, 4,713 merchantable logs were obtainable. Three-fourths (n = 3,552) were 16-foot logs. The other lengths by rank order were 12-, 8-, 14-, and 10-feet, but the range of logs counted between those classes was narrow, n = 282 to n = 298. All but n = 24 of the n = 2,408 butt logs were 16 feet. Trees containing no upper log were n = 437, or 18%. Ten percent of trees contained three merchantable logs.
Projecting stand development and economics of longleaf pine planted outside its native range.
C. VanderSchaaf, Assistant Professor, Louisiana Tech University, Ruston, LA M. Blazier, Professor, Louisiana State University AgCenter, Homer, LA J. Adams, Associate Professor, Louisiana Tech University, Ruston, LA
Probabilistic estimates of costs for treating a southern pine beetle infestation. C. VanderSchaaf, Assistant Professor, Louisiana Tech University, Ruston, LA E. McConnell, Assistant Professor, Mississippi State University, Mississippi State, MS M. Crosby, Assistant Professor, Louisiana Tech University, Ruston, LA J. Holderieath, Assistant Professor, Louisiana Tech University, Ruston, LA J. Meeker, Entomologist, U.S. Forest Service, Pineville, LA C. Steiner, Biological Science Technician, U.S. Forest Service, Pineville, LA B. Strom, Research Entomologist, U.S. Forest Service, Pineville, LA C. Johnson, Entomologist, U.S. Forest Service, Pineville, LA
As part of a regional study of new longleaf pine (Pinus palustris Mill.) genotypes, a site was established at the Louisiana State University Agricultural Center Hill Farm Research Station in northwestern Louisiana to determine growth and development of these genotypes when planted north of the species’ native range. This location is within the projected potential range of longleaf pine under moderate to severe climate change scenarios. In January 2016, the site was hand-planted with 1-0 containerized longleaf pine seedlings in a 10 ft x 10 ft spacing. Treatments consisted of 19 genotypes of diverse geographic origin (Louisiana, Texas, Alabama); 17 genotypes were half-sibling and 2 were full-sibling crosses. Summary statistics and stand tables were calculated by genotype at age 5 and used to conduct projections using a variety of model systems. These projections were used to estimate future economic values, rotation ages, and to see how projections varied among model systems. Projections were conducted using the USDA Forest Service Forest Vegetation Simulator (FVS), the Growth, Yield and Carbon Balance Model For Planted Longleaf Pine, other published models, and mixed-effects models fit using other species. Bark beetles, such as the southern pine beetle (SPB), Dendroctonus frontalis Zimmermann, have historically been the major insect threat to the economically important southern yellow pines (Pinus spp.) in the southern United States. Of Mississippi’s 19.2 million acres of forestland, the Bienville National Forest (BNF) comprises 178,000 acres in central Mississippi. Many of the BNF’s southern pine timber stands unfortunately suffer from overstocking and stagnated timber growth, which created ideal conditions for the SPB outbreak that occurred there between 2015-2019. In 2017, cut-and-leave treatments were applied to infested areas within the forest in an attempt to mitigate SPB spread. Contractors treated 330 different spots on the BNF, at a cost of $645 per acre. The spot and cost data was obtained in an effort to provide a probabilistic assessment of treatment costs for the forest. Program Evaluation and Review Technique using a Beta distribution (i.e., PERT-Beta) and Weibull distribution were selected to estimate treatment costs. The PERT-Beta 90% confidence interval estimates treatment costs between $839-$12,320 but overestimates spot size probability. Evaluation of the data using the Weibull distribution are underway and will be compared with the PERT-Beta results. This information could be used to inform cost estimates for planning/mitigation efforts for future outbreaks on this or comparable forests.
Tuesday, March 16, 2021 3:00-5:00 POSTER SESSIONS
SESSION 3: A, B, C, D, E, F
SESSION 3B – Forest Pests
Tracking the extent and severity of a southern pine beetle outbreak.
M. Crosby, Assistant Professor, Louisiana Tech University, Ruston, LA E. McConnell, Assistant Professor, Mississippi State University, Starkville, MS J. Holderieath, Assistant Professor, Louisiana Tech University, Ruston, LA M. Funderburk, Undergraduate Research Assistant, Louisiana Tech University, Ruston, LA
The Bienville (BNF) National Forest in central Mississippi has been severely affected by a Southern Pine Beetle (SPB) outbreak that began in 2015. In recent years (2018 & 2019), the Forest Service has acquired digital, high resolution (<1m) imagery from low-level aerial flights. The imagery obtained includes all land within the boundary of the BNF, which is approximately 178,000 acres. Areas impacted by SPB were assessed by manually classifying imagery to delineate areas of stressed and dead trees in the BNF. Through 2019, approximately 16,000 acres have been classified as being impacted by and/or treated for SPB infestation. Baseline delineation and classification (active infestation, standing dead, cut and leave, or cut and remove) of impacted areas, by year, provides resource managers information on the extent of damage and a spatial delineation of resource allocation (e.g., manpower, salvage efforts, etc.). This information will be invaluable for future efforts of improving and management and response protocols to similar outbreaks in southern pine forests.
J. Meeker, Entomologist, U.S. Forest Service, Pineville, LA C. Steiner, Biological Science Technician, U.S. Forest Service, Pineville, LA B. Strom, Research Entomologist, U.S. Forest Service, Pineville, LA C. Johnson, Entomologist, U.S. Forest Service, Pineville, LA
Seasonal light response curves of Ligustrum sinense. T. Markus, MFR-Student, Clemson University, Clemson SC G. Wang, Professor, Clemson University, Clemson, SC
Chinese privet (Ligustrum sinense Lour.) is an invasive shrub species in the Southeast U.S. This invasive shrub appears to invade disturbed areas along roadsides, stream systems, and moist depressions. The foremost concern of Chinese privet’s invasion is its ability to displace native plant communities due to its highly competitive nature, further depleting pollinator and wildlife communities. Chinese privet’s full invasive potential of its invaded range remains unclear. Extended leaf phenology (ELP) is an adaptation where plants take advantage of sunlight during the dormant season of deciduous forests when foliage is absent in the canopy. Chinese privet’s semi-evergreen to evergreen characteristic may allow it to use ELP to gain additional carbon through photosynthesis enabling a competitive advantage. Determining the ELP of Chinese privet requires measuring the species’ photosynthetic activity during the dormant seasons. A gas exchange analyzer, CIRAS-2 with the PLC-6 cuvette (PP Systems), is used to create light response curves of Chinese privet. The CIRAS-2 is programmed to record the photosynthetic rate (Ps) at known light transmittance levels from high to low (2000-0 mol/s). I hypothesize the highest rate of photosynthesis activity of Chinese privet will occur during the warmer months at the beginning and end of winter due to the increased light available in the understory of deciduous forests. The information from the seasonal light response curves will further our understanding of Chinese privet’s ELP potential. Understanding an invasive species’ inner workings will help determine how it competes with native species, further allowing for better management decisions.
Immature emerald ash borer population dynamics and parasitoid effects.
P. Phillips, Undergraduate Research Assistant, University of Arkansas at Monticello, Monticello, AR M. Bataineh, Associate Professor, University of Arkansas at Monticello, Monticello, AR
Soil chemical changes following bark beetle-infested wood decomposition. K. Pace, Graduate Research Assistant, Mississippi State University, Starkville, MS
C. Siegert, Associate Professor, Mississippi State University, Starkville, MS J. Tang, USDA Forest Service, Starkville, MS, N Clay, Louisiana Tech University, Ruston, LA R. Hofstetter, Northern Arizona University, Flagstaff, AZ O. Leverón, Universidad Nacional de Ciencias Forestales, Siguatepeque, HN
The emerald ash borer, Agrilus planipennis (EAB), is a non-native invasive insect that was detected in Michigan in 2002 and in Arkansas and Louisiana in 2014 and 2015, respectively. EAB may result in the functional extirpation of North American ash (Fraxinus spp.). Regulatory response in the form of quarantine establishment to slow EAB spread and ash tree mortality aimed to restrict the movement of ash nursery stock and products including firewood from known infested areas. Release of biocontrol agents aimed to reduce EAB population densities and augment quarantine establishment response. Three exotic hymenopteran parasitoids were approved and released nationwide, including releases at three field sites in southwestern Arkansas. The objectives of this study were to examine changes in population demography of EAB immatures and quantify stage/instar-specific mortality rates and potential mortality agent, including parasitism by native and exotic parasitoids. Timing of immature stages and their effects on timing of parasitoid releases and EAB net population growth at these sites will also be discussed. Pine bark beetles are a frequent source of mass tree mortality in pine forests. Bark beetles vector blue stain fungi to attacked trees, leading to a hypothesized preferential attraction of termites to blue stain-inhabited wood. This may accelerate decomposition resulting in a change in terrestrial biogeochemical cycles. Of particular interest are bark beetle-infested forests that are cut to prevent further outbreaks but where wood is left as slash, creating an extraordinarily large woody biomass pool for decomposition. To evaluate the flux of carbon and nitrogen from decomposing wood to soil, a 2 year decomposition study was established with replicate trials in Arizona, Mississippi, and Honduras to record changes in soil chemistry beneath decomposing pine logs from trees attacked by bark beetles and from non-attacked trees. A secondary caging treatment was implemented to isolate the contributions of above- and below-ground decomposer invertebrates. In Arizona, caging treatments led to differences in A horizon carbon and nitrogen in year 1, where carbon was 52.9% higher (p=0.032) and nitrogen was 61.93% higher (p=0.023) under non-caged logs than aboveground-caged logs. Wood source treatments led to differences in soil carbon and nitrogen in year 2, where nitrogen was 11.3% higher in the A-horizon (p=0.046) and 27% higher in the B-horizon (p=0.028) below beetle-infested wood. In Mississippi, wood source treatments led to differences in soil carbon and nitrogen in year 1, where A-horizon carbon was 10.6% higher (p=0.039) and nitrogen was 11.7% higher (p=0.081) in year 1, but there were no differences between treatments in year 2.
Tuesday, March 16, 2021 3:00-5:00 POSTER SESSIONS
SESSION 3: A, B, C, D, E, F
SESSION 3C – Forest Soils and the Forest Floor
Breast level height displacement: do standing trees sink into the soil?
C. VanderSchaaf, Assistant Professor, Louisiana Tech University, Ruston, LA B. Zeide (Deceased) W. Patterson, Associate Professor, Louisiana Tech University, Ruston, LA
Comparing physiochemical properties and sorption behaviors of pyrolysisderived and microwavemediated biochar. C. Brickler, Research Assistant, Tallahassee, FL Y. Wu, Research Assistant, Tallahassee, FL S. Li, Assistant Professor, Pomona, CA A. Swamy, Assistant Professor, Tallahassee, FL G. Chen, FL
As trees grow, their weight and size increases. Increases in the above-ground biomass (bole, crown) may result in trees sinking due to gravity and the corresponding decrease in the original breast height level (dbh; 4.5 ft), further referred to as displacement. Below-ground increases in biomass (roots) push the soil up and out and may result in raising the ground level. We believe both forces are at work and partially offset one another. These phenomena may produce errors when using dbh to predict volume. Remeasuring diameter at the same level across time removes this complication. We noticed that lines (stripe of white paint) placed at age 12 and periodically remarked in a 43-yr-old pine (Pinus taeda L.) plantation are lower than 4.5 feet above the ground-level, especially for larger trees. The objective of this study is to determine whether trees at 43 years of age have had their dbh level changed because of displacement and/or ground-raising. Results showed some force has caused these trees to rise over time from ground-level at the time of planting, most likely roots pushing the tree up because of a high clay content which provides resistance to root expansion. Part of this soil “rise” around trees is offset by the tree sinking due to weight, but apparently the expansion force of roots is greater than the force of gravity pushing the tree downward. Tree dbh should be permanently marked during the establishment of studies to prevent errors being made when determining both dbh and volume.
Biochar’s ability to amend and remediate soil has been a growing interest, though the energy expenses from high-temperature pyrolysis deter the product’s use. Three types of feedstock (i.e., switchgrass, biosolid, and water oak leaves) were used to produce conventional slow pyrolysis-derived biochar at different temperatures, while other biochar was synthesized via microwave-mediation at various power/time inputs. The products were characterized for their physiochemical properties, including surface functionality, elemental composition, recalcitrance, and thermal stability. Through comparison, it was discovered that microwave-mediated biochar was more resistant to thermal decomposition, indicated by a higher production yield, yet more diverse surface functional groups were preserved than pyrolysis-derived biochar. Pyrolysis-derived biochar displayed larger specific surface areas up to five times that of microwave-mediated biochar, which only had an observed maximum specific surface area 10 m2 g-1. Isotherm experiments displayed that microwave-mediated biochar exhibited adsorption of nitrate nitrogen (NO3--N) similar or up to four times (maximum of 13.3 mg g-1) that of pyrolysis-derived biochar (0.25-3.1 mg g-1); which could be attributed to its abundance of hydrophilic groups, proving its potential for future applications. This study aimed at creating a product with similar or better properties as conventional pyrolysis-derived biochar to allow a reduction in production costs through microwave utilization due to the reduced production time required. Results suggested that microwaves with increased power output (at least 3 kW) would be needed to expose the feedstock to a temperature high enough to cause significant thermal transformation, while still having increased nitrogen retention to increase crop yields.
Mass loss and nutrient content of hardwood coarse woody debris in the southern Appalachians 21 years after hurricane Opal. R. Eaton, Biologist, USDA Forest Service, Durham, NC
Effects of forest canopy cover on splash erosion in upland hardwood forests of Mississippi. W. Kruckeberg, Graduate Student, Mississippi State University, Mississippi State, MS C. Siegert, Associate Professor, Mississippi State University, Starkville, MS J. Granger, Assistant Professor, Mississippi State University, Starkville, MS H. Alexander, Assistant Professor, Auburn University, Auburn, AL
It has long been known that coarse woody debris (CWD) has an important ecological role in process and function of terrestrial systems. In southern forests most knowledge of CWD is in relation to the mass and distribution effects on biodiversity resulting from timber management. More recently, studies of the atmospheric carbon budget associated with climate change has broadened interest in decomposition of CWD followed by production of CO2, and accumulation of nitrogen compounds in decayed wood from biological fixation. Production of CWD resulting from forest disturbances may be easily quantified from surveys of newly downed trees however relatively little is known concerning the long-term rates of wood decomposition and chemical changes determined from marked logs of various species in eastern deciduous forests. Canopy gaps created by the remnants of Hurricane Opal in October 1995 provided an opportunity for study of longterm characterization of the dynamics of mass and composition of large diameter CWD. The primary interest in performing the study was to compare the long-term physical and chemical changes of CWD from logs of different tree species and sizes formed by this disturbance event. Four areas that represented canopy gaps of 20 or more wind thrown trees were sampled at years 1, 10, and 21. Percent mass and nutrient loss values will be reported. The throughfall kinetic energy (TKE) and erosivity of rainfall can be estimated using splash cups, which measure the amount of sand lost due to raindrop impact. The degree of splash erosion caused by raindrop impact is related to the kinetic energy transferred upon impact. Studies have suggested that the presence of a forest canopy can increase the kinetic energy of raindrops by aggregating them into larger, heavier, masses. However, more research is needed across more diverse range of forest conditions. Higher sediment detachment from raindrop impact could increase sediment loss and erosion, leading to a reduction of site productivity and water quality. This study used an upland hardwood stand in northern Mississippi to examine how canopy density affected TKE during growing and dormant seasons. Results showed that 70% of TKE variability was explained by interactions between canopy, slope position, and rainfall intensity. TKE was 25% higher in the growing season (19.4 J m-2 mm-1) than in the dormant season (15.5 J m-2 mm-1) (P-Value <0.001), even though total rainfall and rainfall intensity were higher in the dormant season. Analysis showed no correlation between TKE and overland flow or total suspended sediments. Risk of soil detachment from raindrop impact is highest when bare mineral soil has been exposed by disturbances such as fire or forest management. The increased risk of soil loss from bare mineral soil may be mitigated by limiting prescribed fire to the dormant season; however some applications of fire require growing season burns to achieve management objectives.
Tuesday, March 16, 2021 3:00-5:00 POSTER SESSIONS
SESSION 3: A, B, C, D, E, F
SESSION 3D – Measurement and Modeling
Developing a simple longleaf pine plantation growth and yield model for the Gulf Region. C. VanderSchaaf, Assistant Professor, Louisiana Tech University, Ruston, LA
Ability of site index to differentiate merchantable yield in southern yellow pine plantations.
C. VanderSchaaf, Assistant Professor, Louisiana Tech University, Ruston, LA
Linking canopy cover and standard stand density metrics for Wetland Reserve Easements in Arkansas. J. Borland, Undergraduate Research Assistant, University of Arkansas at Monticello, Monticello, AR M. Bataineh, Associate Professor, University of Arkansas at Monticello, Monticello, AR
Longleaf pine (Pinus palustris P. Mill.) forests were thought to once occupy nearly 92 million acres. This species produces valuable wood products but has the stigma of slow growth and hence was often not replanted following harvest. Thus, despite its timber value, only a few growth and yield models have been developed. This study examines four different modeling approaches to estimate merchantable volume of plantations in the Gulf region. Data used in model development are from Forest Inventory and Analysis annual surveys conducted in Alabama, Florida, Louisiana, Mississippi, and Texas. Initially, a site index equation was developed. Two approaches predicted volume as a function of previous volume, one also as a function of age and the other also as a function of age and site quality. A third approach first estimated basal area as a function of age and previous basal area and then predicted volume as a function of basal area and site quality. The fourth approach first predicted a diameter distribution and then stand-level volume was estimated. Based on independent validation data from four different studies, one each in Mississippi and Alabama and two in Georgia, the approach predicting volume as a function of initial volume and age and the approach that first predicts basal area and then volume produced the best predictive statistics. However, neither approach was consistently best across all four validation studies. The two other approaches produced inferior predictive statistics. Based on these analyses, a single superior modeling approach was not identified. An estimate of site quality is often used to predict yields and to differentiate the ability of management units to meet a particular objective.Site index is commonly used. Site index is thought to be a collective influence of soil factors and climatic conditions. This study attempted to quantify if site index temporally consistently ranks a site’s ability to produce a particular product for loblolly, slash, and longleaf pine. For each species, four replications were established of ten different cultivation and fertilization combinations (n = 120). Each of the 40 plots by species were assumed to represent a different stand. Total height and dbh were measured and volumes were subsequently estimated at ages 8, 25, and 39. Site index was defined as the average height of the tallest half of surviving trees at age 25. The site index of each plot and yields by plot were ranked. Rankings of site index and yield by plot were paired and examined for correlations at a particular age and for consistency across time. The rankings of volumes were strongly linearly related to site index rankings within a particular age, loblolly had the least amount of variability. Correlation values of volume and site index rankings for total and pulpwood volume decreased across time, particularly for slash. However, sawtimber production correlations increased across time. Loblolly showed the most consistency among site index and yield rankings across time for a particular product. Longleaf showed less variability relative to slash for all product classes but sawtimber. Forest canopy cover estimates are widely applied metrics in habitat management, forest structure analysis, and forest health analysis. Canopy cover estimates are used as threshold values for triggering management actions and determining desired forest conditions. Canopy cover estimates are difficult to obtain for entire forest tracts but correlate relatively well with other more easily determined stand metrics. Using traditional forest inventory data coupled with canopy cover and openness metrics derived from hemispherical photography and WinSCANOPY analysis software, we correlate density and cover to provide a practical translation to be used by forest resource managers and researchers. WinsCANOPY allows for the adjustment of metered brightness in hemispherical photographs for which the light contrast has been made absolute, resulting in a black and white image of polygons which represent canopy cover. Cover estimates will be regressed against estimates of basal area and trees per acre to provide standardized predictive estimates of canopy cover proportion.
Using national inventory data (FIA) to explore the relationship between diversity and productivity in Mississippi forests. E. Baach, Graduate Student, Mississippi State University, Starkville, MS
A. Himes, Assistant Professor, Mississippi State University, Starkville, MS
Numerous studies have evaluated the relationship between biodiversity and productivity, with general global trends suggesting a positive relationship, even with studies finding negative or neutral relationships. We know of no studies that investigate this relationship in Southeastern US forests despite high levels of tree species diversity. Most studies in forest systems have relied on tree species richness as the primary indicator of biodiversity and productivity to indicate ecosystem function. We will analyze the impact of functional diversity and richness on forest productivity. This is of particular importance as functional groups provide a more comprehensive meaning to diversity compared to traditional taxonomic classifications, as functional groups are directly based on the relationship between an organism, or group of organisms, and their environment. The use of functional diversity will give important context to the examination of forest productivity due to the direct link it establishes between organisms and their role in a given ecosystem. We will use data from the USDA Forest Service Forest Inventory and Analysis (FIA) database collected in the state of Mississippi. We will determine plot level productivity as the difference in tree biomass between repeated measurements. Functional diversity will be characterized by tree type, and regression methods will be used to determine the strength and direction of the relationship between tree functional diversity and productivity. Based on previous studies that examined the relationship between biodiversity and productivity as well as studies that examined the relationship between functional diversity and ecosystem function, we hypothesize a positive relationship.
Tuesday, March 16, 2021 3:00-5:00 POSTER SESSIONS
SESSION 3: A, B, C, D, E, F
SESSION 3E – Natural Disturbances and Climate Change
Longleaf and lasers: improving models for wind susceptibility in the Coastal Plain. C. English, Research Technician, Jones Center at Ichauway, Newton, GA
J. Cannon, Forest Management Scientist, Jones Center at Ichauway, Newton, GA K. Hiers, Wildland Fire Scientist, Tall Timbers Research Station, Tallahassee, FL
Forests in the coastal plain of the Southeastern United States are particularly vulnerable to wind damage from increasingly frequent and powerful hurricanes. Understanding factors influencing wind risk to forests can improve predictions of hurricane impacts on forest ecosystem dynamics, structure, and function at large spatial and temporal scales. Mechanistic models to predict wind damage have been developed that link tree and stand structure to wind susceptibility. Accurate measurement of tree parameters including crown area can substantially impact final critical wind speed values and may be improved through advancing technologies. We used a terrestrial laser scanning system in second growth Pinus palustris stands with a range of ages and densities to determine crown characteristics using a response surface experimental design. We found crown area increased with tree diameter and differed depending on assumptions of crown shape. A high resolution voxel method predicted 10% less vertical crown area than the standard diamond method employed for modeling windfirmness in conifer species. Additionally, we report crown allometric relationships based on tree size and stand basal area for Pinus palustris for use in wind modeling and other ecological studies. Current mechanistic models of wind damage that assume simple geometries may overestimate wind susceptibility, particularly in medium-high density longleaf stands where actual crown area deviates significantly from diamond geometry. Improved understanding of longleaf crown characteristics and their impacts on wind susceptibility can aid in understanding forest dynamics following disturbances and also inform management strategies for mitigating wind risk in the hurricane prone forests of the Southeast.
Growth response of mature longleaf pine to disturbance at the Harrison Experimental Forest. J. Butnor, Research Plant Physiologist, USDA Forest Service, Southern Research Station, Burlington, VT
R. Eaton, Biologist, USDA Forest Service Southern Research Station, Research Triangle Park, NC D. Nelson, Project Leader, USDA Forest Service Southern Research Station, Lexington, KY
Climate-growth responses among co-occurring upland oak and pine species in East Texas. S. Shroyer, Undergraduate Research Assistant, Stephen F. Austin State University, Nacogdoches, TX T. Jones, Undergraduate Research Assistant, Stephen F. Austin State University, Nacogdoches, TX K. Kidd, Assistant Professor, Stephen F. Austin State University, Nacogdoches, TX
Experimentally measuring effects of soil moisture on windfirmness in Pinus elliottii using static winching.
S. Scully, M.S Research Assistant, University of Georgia Department of Plant Biology, Athens, GA S. Taylor, Senior Research Associate, Jones Center at Ichauway, Newton, GA C. Peterson, Professor, Department of Plant Biology, University of Georgia, Athens, GA J. Cannon, Forest Management Scientist, Jones Center at Ichauway, Newton, GA
Young southern pine plantations are very responsive to resource availability, whether from soil nutrition or access to light. When thinning is timed appropriately, trees develop desirable stem quality and their growth rates are maximized. Less is known about the response of mature trees to natural and silvicultural disturbances. Longleaf pine is a longlived tree that is well suited to extended rotations in the Gulf Coast where natural disturbance from hurricanes periodically occur and thinning for commercial purposes or to create wildlife habitat. We explored the diameter growth of longleaf pine planted in 1961 in the years following disturbances from Hurricane Katrina (2005) and thinning (2011) in at the in Saucier, Mississippi. Winds from Hurricane Katrina destroyed 7% of the longleaf pine, damaging many more, while the thinning was variable, based on existing density. A total of 180 trees were sampled with an increment borer in April 2017 and analyzed to quantify basal area increment (BAI) of both early and late wood. Using BAI normalized to year 2005, we observed that declines of 11 and 13% in 2006-2007, followed by a recovery to 2005 levels by 2011. One year after thinning in 2011, BAI normalized to 2005 increased 50% in 2012, followed by +34%, +8%, +16%, +54% in subsequent years 2013-2016. Clearly the loss of cohort members in 2005 served to reduce stocking levels, but crown damage and loss of foliage likely caused the growth stagnation during next five years. Conversely the thinning was followed by large increases in BAI for two years. Radial stemwood growth in trees can reflect the biological growth response to disturbance events (e.g., droughts, floods, wildfires). These responses are recorded in the form of wood anatomical features and variations in annual ring widths throughout the lifetime of a tree. This study quantified the variation in ring widths in response to climatic disturbances among naturally co-occurring upland loblolly pine (Pinus taeda), shortleaf pine (Pinus echinata), longleaf pine (Pinus palustris), southern red oak (Quercus falcata), white oak (Quercus alba), and post oak (Quercus stellata) across Boggy Slough Conservation Area and the Angelina National Forest in in the East Texas Pineywoods ecoregion. At each site, two cores were extracted from 25 trees for each species tree using a manual increment borer. Cores were visually cross-dated and measured using a Velmex measuring system. Visual cross-dating was validated using COFECHA software, and tree-ring chronologies were developed for each species and site in ARSTAN. NOAA historical weather data (e.g., precipitation, temperature, Palmer Drought Severity Index) were obtained and analyzed for influence on annual growth. Of the oaks, southern red oak displayed the greatest sensitivity and had greater departures in RWI values during and immediately following indicator drought years across both sites. Post oak and shortleaf pine exhibited less annual radial growth on average but appeared to be more resilient to drought conditions than co-occurring species. Responses to climatic events from the aforementioned species provide managers with important information related to species-specific responses to disturbances. Predicting wind impacts from atmospheric events such as hurricanes is challenging, and often relies on observational damage surveys where tree size and soil differences can obscure species variation in windfirmness. Measuring the resistance of southern pines to hurricane forces has not been measured mechanically across a gradient of soil moisture content. We conducted an experimental tree winching study to estimate the critical turning moment to induce stem failure or uprooting in 60 Pinus elliottii (slash pine), a dominant silvicultural species in the U.S. Gulf Coastal Plain. We manipulated soil moisture by adding 500-1000 gal of water within the drip line of target trees to simulate heavy rains associated with hurricanes the evening prior to winching. Our early results suggest that windfirmness increases with tree diameter at breast height (dbh) and decreases with soil moisture percentage. In addition, we found that wetted trees were more likely to uproot rather than snap relative to dry trees. Ongoing studies will allow comparisons of windfirmness among other pine species and provide insights to forest management in windprone areas. In addition, these data are valuable in informing wind disturbance modeling and to help silviculturists understand and mitigate the impacts hurricanes have on slash pine in the southeastern United States.
Tuesday, March 16, 2021 3:00-5:00 POSTER SESSIONS
SESSION 3: A, B, C, D, E, F
SESSION 3F – Silviculture and Management
A photographic record of the first silvicultural research of the Southern Forest Experiment Station. D. Bragg, Research Forester/ Project Leader, USDA Forest Service Southern Research Station, Monticello, AR
Effects of post-fire disturbance responses of Microstegium vimineum on native hardwood seedling regeneration Z. Chandler, Graduate Research Assistant, College of Forest Resources, Columbus, MS A. Himes, Assistant Professor, College of Forest Resources, Starkville, MS
The USDA Forest Service researchers who opened the Southern Forest Experiment Station on July 1, 1921, had to develop a program of studies that met the needs of their constituency. With limited resources, experience, expertise, and no experimental forests to work with, this New Orleans-based staff had few options. Fortunately, they had the foundations of a silviculture project on the lands of the Urania Lumber Company in central Louisiana. In the mid-1910s, Samuel Trask Dana and some other Washington Office staffers had worked with Henry Hardtner to install a rudimentary thinning study in young even-aged stands of loblolly and shortleaf pine. While virtually no records—except these historical photographs and a few summary publications—remain of this pioneering effort, the primary objective was to quantify the response of these stands to “German” (thinning from below) and “French” (thinning from above) approaches at several different levels of intensity (“grades” from light (“A”) to very heavy (“D”)). Several unthinned stands were also monitored to serve as no-treatment contrasts. The handful of initial Â¼-acre study plots established by Dana were expanded upon by researchers from the Southern Forest Experiment Station shortly after the Station opened and maintained into the 1940s. Installed before the widespread use of probabilistic statistics, hypothesis testing, and effective study design, this poorly replicated and inadequately controlled effort would today be considered more of a demonstration than research project. However, the Urania thinning study work suggested the promise of density reductions in overstocked southern pine stands to improve management outcomes. Invasions by alien understory species have gradually become a worldwide challenge in the maintaining forest biodiversity and ecosystem productivity. Of particular importance is Japanese stiltgrass (Microstegium vimineum); an invasive C4 grass native to Japan that possesses several traits that contribute to its invasive and competitive nature. Control of this species has gained awareness as its invasion seeks to dominate mixed deciduous hardwood forests of the southeastern United States, due of its shade tolerance and ability to spread through rhizomes. The potential negative impacts of M. vimineum on native biodiversity and forest productivity has driven managers and researchers to determine its most effective management strategy. Multiple studies have investigated the response of M. vimineum to prescribed fire, though none have focused on its impact(s) on native hardwood seedling reproduction following prescribed fire. Previous research has suggested that the presence of M. vimineum before the prescribed fire would indicate its dominance post-disturbance, significantly hindering hardwood seedling regeneration. Using an upland deciduous hardwood forest research site in Tate County, Mississippi, we hope to measure the competitive effects of M. vimineum on native hardwood seedling regeneration with and without multiple prescribed fire treatments over a range of individual study plots. Our hypothesis suggests increasing the use of prescribed fire in M. vimineum management efforts, as it is determined to be the most efficient and effective strategy for reducing Japanese stiltgrass presence and supporting forest regeneration.
Examining initial effects of planting stock differences on growth and survival in an artificially regenerated shortleaf pine restoration in the Southern Appalachian Mountains. A. MacDonald, Student, Western Carolina University, Cullowhee, NC T. Keyser, Research Forester, U.S. Forest Service, Asheville, NC
Sprouting response of three-year-old planted shortleaf pine one growing season year after prescribed fire in East Texas. J. Wilkins, Undergraduate Research Assistant, Stephen F Austin State University, Nacogdoches, TX K. Kidd, Assistant Professor, Stephen F Austin State University, Nacogdoches, TX S. Shroyer, Undergraduate Research Assistant, Stephen F Austin State University, Nacogdoches, TX B. Oswald, Professor, Stephen F Austin State University, Nacogdoches, TX S. Jack, Executive Director, Boggy Slough Conservation Area, T.L.L. Temple Foundation, Lufkin, TX
Shortleaf pine (Pinus echinata) restoration efforts in southern forests have been at the forefront in recent years with an increasing emphasis on mixed pine-hardwood management. Shortleaf pine is the most widely distributed southern yellow pine species, found in 23 states in a variety of forest types and geographic conditions. Shortleaf pine was historically a prominent component of southern Appalachian forests but has continued to decline throughout the region due to land use change, changes in historic disturbance regime, and southern pine beetle (Dendroctonus frontalis) outbreaks. Most of the information available on shortleaf and mixed pine-hardwood restoration and management is specific to the western portion of its natural range (e.g., Arkansas, Missouri). In 2015 a study was established in the Pisgah National Forest to examine the restoration of a mixed-shortleaf pine-oak forest system in the southern Appalachians. A shelterwood with reserves regeneration harvest and site preparation activities, including the slash-down of non-merchantable material followed by a cut stump herbicide treatment to prevent sprouting of non-desirable species, were conducted. Site preparation burns were then conducted 6 to 12 months following harvest in all stands and two artificial regeneration treatments were applied. Treatment one included planting 1-0 bare root shortleaf pine seedlings; Treatment two included the planting of 1-0 containerized shortleaf pine seedlings. Initial survival and growth rate differences of artificially regenerated shortleaf pine seedlings planted using two different planting stocks (container versus bareroot) and artificially regenerated shortleaf pine response to hardwood competition following the first three years post establishment are discussed. Programs (e.g., The Shortleaf Pine Initiative) that encourage planting and management of shortleaf pine (Pinus echinata) have increased in popularity. However, many questions related to management guidelines and timelines remain. Such questions include: how early to burn in a plantation setting? and if aboveground topkill occurs, will resprouting response be similar to naturally regenerated shortleaf seedlings/saplings? This study quantified the effects of a single dormant season fire on mortality and sprouting response in two-6 acre, three-year-old planted shortleaf pine stands located on the Boggy Slough Conservation Area in East Texas. Stands burned were hand planted on a 7.25 x 12 ft. spacing in January 2017 and received a prescribed fire in February 2020. Severity was assessed one month following treatment to capture crown scorch occurrence. One growing season following the fire treatment, the majority of stems had either lost all foliage or had > 60% of foliage scorched during fire. Nearly all of these stems had produced at least one basal sprout. Stems impacted at a greater severity produced a greater number of basal sprouts. Results from this study highlight the importance of ensuring the firing plan is developed to burn at a low intensity to reduce mortality in young pine stands, even fire-adapted shortleaf pine. Sprout dynamics will be followed through time to quantify viability and growth from rootstocks where aboveground topkill occurred.
Wednesday, March 17, 2021 9:00-10:00 CONCURRENT SESSIONS SESSION 4: A, B SESSION 4A – Loblolly Pine Management II
Biography of Russell R. Reynolds, a pioneering Forest Service silviculture researcher.
D. Bragg, Research Forester/ Project Leader, USDA Forest Service, Southern Research Station, Monticello, AR
A reevaluation of superior tree performance after 48 years for a loblolly pine progeny test in southern Arkansas.
D. Bragg, Research Forester/ Project Leader, USDA Forest Service, Southern Research Station, Monticello, AR
In 1930, Michigan native Russell R. Reynolds was hired by the USDA Forest Service’s Southern Forest Experiment Station shortly after he received his forestry degrees from the University of Michigan. After working on projects related to timber inventories, logging practice time-and-motion studies, and truck-based operations, Reynolds was assigned a case study with the Ozark Badger Lumber Company in Drew County, Arkansas, which led to a 1933 project with the Crossett Lumber Company in nearby Ashley County. Officials with the Crossett Lumber Company were sufficiently impressed with Reynolds and the prospects of sustainable forestry to offer the Forest Service a 1,680-acre parcel of land to study silvicultural practices in loblolly and shortleaf pine-dominated second-growth forests typical of the Upper West Gulf Coastal Plain. Following the January 1, 1934, opening of the Crossett Experimental Forest (CEF), Reynolds spent the next 35 years working on silvicultural challenges and opportunities in naturally regenerated southern pine forests. Reynolds focused his research on refining the practice of uneven-aged silviculture. Always a practical purveyor of knowledge, he also helped to pioneer the concept of “farm forestry” for small forest landowners, and conducted innumerable tours, field days, and silviculture-based training workshops. While best known for his work in uneven-aged silviculture and knowledge transfer, Reynolds also developed the CEF into a premiere research and demonstration center supported by a cadre of other scientists that generated many studies on forest soils, growth and yield, pine regeneration, even-aged management, competition control, and forest genetics/tree improvement in these southern pine-dominated ecosystems. A plus-tree progeny test of full- and half-sib loblolly pine (Pinus taeda) was installed in 1969 on the Crossett Experimental Forest (CEF) to compare the performance of 28 “improved” families with “woods-run” planting stock from the CEF (family W29). Performance outcomes were compared using data from young (<10-year-old; early 1970s), maturing (25-year-old; 1994), and mature (48-year-old; 2017) trees. With the exception of a single improved family, early survival was high (>80%), with most families exceeding 90%. Three years post-planting, fusiform rust infection rates were also low, with most families having less than 1% of seedlings infected and the highest rate was only 2.2%. When compared at this stage early stage, the unimproved CEF family W29 only slightly underperformed the best full- and half-sib superior families. By 1994, W29 had slightly higher than average merchantable volume. This trend continued for W29 when remeasured in 2017, with the average merchantable volume yield for W29 statistically similar to the most productive families. This study shows that only limited volume performance gains from crossing plustrees. However, it was important to note that several of the best height growth-performing families in 1972 were not the highest merchantable volume producers at 25 or 48 years, and some of the worst early performers moved into the upper tiers by the later remeasurements. These outcomes suggest that depending solely on early height performance to select families for long-term volume yields may not be the best approach.
Crown lifting techniques for maintaining stem quality in widely spaced pine plantations. D. Collins, Graduate Research Assistant, Mississippi State University, College of Forest Resources, Department of Forestry, Mississippi State, MS
J. Granger, Assistant Professor, Mississippi State University, College of Forest Resources, Department of Forestry, Mississippi State, MS S. Dicke, Professor Emeritus, Mississippi State University, College of Forest Resources, Department of Forestry, Mississippi State, MS
Crown lifting, or the manual pruning of lower branches, in combination with wider tree spacing offers an alternative management scheme for small non-industrial private forest landowners who have experienced difficulties with having their pine plantations thinned. The study was established in May of 2003. A five-year-old loblolly pine (Pinus taeda) plantation was thinned to 200 trees per acre, with an average spacing of 14.8 feet between trees. Five crown lifting treatments were then implemented: a control, 35, 40, 45, and 50% live crown ratios (LCR), which is the percent of total height with branches. Branches were removed from the bole of the tree just outside the branch-bark ridge. Two replications were established for all treatments, with a plot size of 0.12 acres and an average of 24 trees per plot. The desired LCR was maintained through repeated crown liftings in 2003, 2004, and 2008. At age 8, the average diameter of the control group was 5.3 inches, and the diameter of the 50% LCR treatment was 8.2 inches. The trees treated with the 50% LCR produced the greatest diameter growth compared to all other treatments. The highest mortality rate (12.5%) was observed in the 45% LCR treatment. Wide spaced plantings maintained with pruning could allow small forest landowners to obtain a high-value sawtimber product, while eliminating the need for the thinning cuts commonly used in traditional pine plantation management.
C. Hale, Graduate Research Assistant, Mississippi State University, College of Forest Resources, Department of Forestry, Mississippi State, MS
Response duration after a mid-rotation fertilizer application in Pinus taeda. T. Albaugh, Research Associate, Virginia Tech, Blacksburg, VA D. Carter, Assistant Professor, Virginia Tech, Blacksburg, VA C. Cohrs, Graduate Research Assistant, North Carolina State University, Raleigh, NC R. Cook, Associate Professor, North Carolina State University, Raleigh, NC R. Rubilar, Professor, Universidad de Concepción, Concepción, NC O. Campoe, Assistant Professor, Federal University of Lavras, Lavras, NC
Fertilization is a useful silvicultural tool for managers in nutrient limited loblolly pine (Pinus taeda L.) stands in the southeastern United States. Recent work indicated that stands may benefit from multiple applications of nitrogen and phosphorus beginning in 2 to 3 year old stands and lasting throughout the rotation. However, single mid-rotation applications of nitrogen (N) and phosphorus (P) are commonly used. Managers would benefit by knowing the duration of positive response from a one-time application of N+P in order to capture all the value from fertilization and coordinate fertilization with other stand activities including final harvest. Our interest was quantifying duration of measurable response to a one-time mid-rotation application of N+P on sites where there was a significant fertilizer response (indicating the stand was in fact nutrient limited). We examined 310 stands where N was applied at 100, 200, or 300 lbs ac-1 elemental N with at least 25 lbs ac-1 of elemental P and where there was a positive fertilizer response in the cumulative 8 year volume measurements. With the 200 lb ac-1 N dose, the average increment response over time was 22, 78, 79, 70, 30, 42 ft3 ac-1 yr-1 for 1, 2, 4, 6, 8 , and 10 years after treatment, respectively. The 100 and 300 lbs ac-1 nitrogen applications followed similar patterns over time but with slightly lower and higher annual responses, respectively. However, we observed considerable variation around these means and plan to examine soils, physiography and other stand characteristics to explain this variation.
Wednesday, March 17, 2021 9:00-10:00 CONCURRENT SESSIONS
SESSION 4: A, B
SESSION 4B – Natural Disturbances and Climate Change II 9:00-9:15
A stand level application of efficiency analysis to understand efficacy of fertilization and thinning with drought in a loblolly pine plantation.
N. Shephard, Graduate Research Assistant, Oklahoma State University, Stillwater, OK O. Joshi, Assistant Professor, Oklahoma State University, Stillwater, OK C. Meek, Assistant Superintendent of the Kiamichi Research Station, Oklahoma State University, Stillwater, OK R. Will, Professor, Oklahoma State University, Stillwater, OK
Loblolly pine (Pinus taeda L.) is the most important and productive commercial timber species in the southern USA. While plantation management practices such as fertilization and thinning are commonly recommended for higher economic returns, their efficiency and cost-effectiveness are unknown given anticipated climate change effects, such as increased drought severity, especially in the drier Upper Gulf region of the south-central USA. To calculate technical and economic efficiency, we used data envelopment analysis (DEA) to assess the ability of fertilized, thinned, and drought-induced loblolly pine plots in southeastern Oklahoma (n=32) to turn volume growth and stand density (inputs) into timber products- pulpwood, chip-n-saw, sawtimber- and stored carbon (outputs) across 21, 26, and 31-year rotations We found that thinned stands remain technically, economically, and overall efficient as rotation age increased. Non-thinned stands had lower efficiencies than thinned stands and exhibited a 28% decrease in overall efficiency between ages 21 and 31. Drought decreased overall efficiency by at least 11% when the rotation age was 26 years or longer. Fertilization with drought decreased overall efficiency on average by 24%. The results reiterate the importance of thinning to efficiently mediate drought conditions and should remain a staple of plantation silviculture. Results also indicate that fertilization is not likely to help ameliorate drought impacts, from an efficiency standpoint. Study results will benefit practitioners in gauging active forest management decisions and their likely outcomes from a resource-use perspective.
A. Susaeta, Assistant Research Scientist, University of Florida
Effectiveness of commercially available Japanese stilt grass (Microstegium vimineum) control methods. C. Beam, Graduate Student, Mississippi State University
C. Siegert, Associate Professor, Mississippi State University J. Granger, Assistant Professor, Mississippi State University R. Iglay, Assistant Professor, Mississippi State University
Microstegium vimineum (Japanese stilt grass) is an invasive grass species that has spread heavily throughout the United States, particularly in bottomland areas and closed canopy forests. M. vimineum can establishes a dense monoculture in the understory of these stands and inhibit the regeneration of native species. There are limited direct comparisons regarding treatment option effects and the application timing on the control of for M. vimineum. To fill this knowledge gap, a randomized complete block design was established in the Piedmont region of North Carolina to compare four treatment options (glyphosate application, mechanical removal, manual removal, and vinegar application) and three application times (spring, summer, and fall). Prior to treatment and six weeks post treatment, plots were measured for M. vimineum coverage and species richness, using a method of ocular estimation and Shannon’s index, respectively. Results showed that the application of glyphosate was highly effective in all three application times (95-100% reduction) and that the application of vinegar was highly effective in the summer and fall applications (90-100% reduction). Results pertaining to species richness showed a larger amount of species present in all treatment plots as opposed to the control plot. These results provide preliminary evidence of the effectiveness of several common treatments of M. vimineum that are accessible to landowners and how each treatment affects biodiversity.
Mapping forest restoration in Lower Mississippi Alluvial Valley. N. Rai, Student, Mississippi State University, Starkville, MS Q. Ma, Assistant Professor, Mississippi State University, Starkville, MS J. Yang, Assistant Professor, Mississippi State University, Starkville, MS
Connecting strategic planning with forest operations using the Forest Adaptive Management Online User System (FAMOUS). E. Paradiso, Research Assistant, USDA Forest Service/SRS/EFETAC/ SE Climate Hub, Research Triangle Park, NC
S. McNulty, Director/Research Ecologist, USDA Forest Service/SRS/ EFETAC/SE Climate Hub, Research Triangle Park, NC M. Gavazzi, Director/Research Ecologist, USDA Forest Service/SRS/ EFETAC/SE Climate Hub, Research Triangle Park, NC K. Bakken, Research Scientist, USDA Forest Service/SRS/EFETAC/ SE Climate Hub, Research Triangle Park, NC E. Worley, Research Assistant, USDA Forest Service/SRS/EFETAC/ SE Climate Hub, Research Triangle Park, NC
Remote sensing techniques have been widely used in forest resource assessment and biodiversity studies. Remotely sensed data are being used to efficiently monitor forest restoration around the world. Forest restoration has been applied over the Lower Mississippi Alluvial Valley (LMAV), USA over the past decades, but their impacts have not been fully evaluated at regional scales. This research is intended to provide a versatile tool to map forests on a multi-spatial and temporal scale to facilitate the evaluation process. This study maps forest height over LMAV using remotely sensed observations from satellite imagery and spaceborne LiDAR data. The generated tree height observations were compared among various vegetation types and areas experiencing different disturbances over different times and locations. These data demonstrate the trend in forest structure transformation over time, and how these changes have resulted in the changing quality of forests. This suggests which forest management practices need to be introduced in these circumstances more efficiently and cost-effectively. The ultimate goal of this study is to generate wall-to-wall vegetation height and biomass maps at fine spatial resolution. These maps will provide valuable information to evaluate the impacts of forest disturbance on ecosystem values in terms of wildlife habitat and climate change mitigation, prioritize efforts for forest restoration, as well as helping to improve forest management sustainably, and assist in strategic planning. Forests in the southeast United States have always been impacted by wildfires, storms, insects, diseases, and other threats. However, climate change is amplifying these risks and adversely affecting forest productivity and resilience. To meet this challenge, forest managers need tools based on the most current science that enables informed decision-making to increase forest resilience to disturbance and reduce the risk of catastrophic loss. While stand-alone resources (e.g., SAF Forestry Handbook) are available to assist with forest planning and management, they fail to fully connect strategic planning with management options that consider multiple threats and modifications to traditional management practices. Therefore, we are developing the Forest Adaptive Management Online User System (FAMOUS), which will prescribe management options by integrating scientific literature addressing climate change impacts on forestland in the southeast US with traditional silvicultural practices. FAMOUS combines two tools: Template for Assessing Climate Change Impacts and Management Options (TACCMIO) and Forest Operation Resource Tool (FORT). TACCIMO has findings from the most current peer-reviewed scientific research detailing how climate change is altering forest ecosystems. FORT provides operational level guidance for managing forest stands using traditional silviculture. FAMOUS is a first-generation tool that sorts, compiles, and displays stand-level climate change specific recommendations across the southeast US’s ecoregions. As a user-friendly, real-time forest management tool, FAMOUS will provide climate-adaptive management prescriptions for private, state, and national forests.
Wednesday, March 17, 2021 10:00-12:00 CONCURRENT SESSIONS
SESSION 5: A, B
SESSION 5A – Longleaf Pine Management
Can longleaf pine plantations be modeled by calibrating mixed-effects models of other species?
C. VanderSchaaf, Assistant Professor, Louisiana Tech University, Ruston, LA H. Burkhart, Professor, Virginia Polytechnic Institute and State University, Blacksburg, VA M. A. Sayer, Plant Physiologist, USDA Forest Service, Southern Research Station, Pineville, LA
Survival, growth, carbon isotope discrimination and cold tolerance of wideranging provenances of longleaf pine grown in the northern edge of its range. K. Johnsen, Scientist, USDA Forest Service Southern Research Station, Asheville, NC J. Butnor, Scientist, USDA Forest Service Southern Research Station, Burlington, VT J. Creighton, Research Manager, Virginia Department of Forestry, Charlottesville, VA C. Maier, Scientist, USDA Forest Service Southern Research Station, Research Triangle Park, NC P. Schaberg, Scientist, USDA Forest Service Northern Research Station, Burlington, VT G. Hawley, Research Associate, University of Vermont, Burlington, VT
A growth and yield model system applicable for the relatively greater growth rates of more recently planted longleaf pine (Pinus palustris Mill.) is needed. The present analysis uses mixed-effects models of other pines fit using measurements across a more complete range of stand development stages to predict the future development of contemporary longleaf pine plantations. This approach could be useful when there are insufficient measurement ages across a rotation for newer silvicultural treatments. Gains in using more than one basal area measurement in the calibration process were also examined. Basal area was used for calibration because it is not dependent on other relationships such as individual tree volume equations. To estimate volume, users can select volume-basal area ratios they regard applicable to their stand. Testing data were obtained of container-planted longleaf pine arranged in a 7.87- by 7.87-ft spacing in central Louisiana. Mixed-effects models both published and newly fit were used for testing purposes. Models were fit using loblolly pine (Pinus taeda L.), ponderosa pine (Pinus ponderosa Lawson & C. Lawson), and red pine (Pinus resinosa Aiton) and in combinations of those species. Initial analyses showed the approach generally produced improved predictions of longleaf at age 20. For a particular model, predictive ability generally improved as the number of basal area measurements, or the number of observations used in calibration, increased. Longleaf pine now occupies less than five percent of its pre-European extent. Concerted efforts are being made to restore the species including in Virginia which represents the extreme northern edge of its historical range. There is only one remaining population of longleaf pine in Virginia which makes the use of local genotypes risky due to potential lack of genetic variation. Here we examine the height growth, survival, volume, carbon isotope discrimination and cold tolerance of provenances ranging from Mississippi to Virginia grown on three sites in Virginia. Trees from the Virginia provenance initially grew faster than the southern provenances but by year 5 there were no differences in height growth among all the provenances. The Virginia provenance had significantly and substantially lower foliar 13C discrimination (indicting higher water use efficiency) at year 5 than the other provenances but it was only weakly related to growth on one site. At year 10 survival of southern provenances declined over time with survival of the Virginia provenance being highest with volume decreasing with latitude. Surviving trees shows cold hardiness at year 10 showed no variation among any of the provenances. This indicates that pre-adaptive variation in cold tolerance exists in southern populations. Although the Virginia population appears best suited for planting in its local habitat, because of its limited population size we discuss the idea of blending seed from a range of provenances to plant in the northern edge of its range to increase genetic variation in restored sites and on sites where assisted migration northward might be of interest.
Linkage between longleaf pine seedling morphology and emergence from the grass stage.
M. A. Sayer, Plant Physiologist, USDA Forest Service Southern Research Station, Alexandria Forestry Center, Pineville, LA S. Sung, Plant Physiologist, USDA Forest Service Southern Research Station, Pineville, LA
23-Year impacts of biannual seasonal burning and alternative understory treatments on longleaf pine productivity. J. Willis, Research Forester, US Forest Service, Auburn, AL
A. Sharma, Assistant Professor, University of Florida, Milton, FL J. Kush, Retired, Auburn University, Auburn, AL
Artificial regeneration is an important means of longleaf pine restoration. Cultural conditions that minimize the grass stage and thus, accelerate juvenile growth, increase the attractiveness of this species to private landowners. Relationships between absorbing root mass, leaf surface area, and cross-sectional sapwood area reflect the supply of water for carbon fixation and growth in mature trees. It is hypothesized that emergence from the grass stage is also correlated with water supply and carbon fixation which are controlled by morphological relationships that favor seedling hydraulic function. A greenhouse experiment was conducted to determine if relationships between the root system variables, leaf area, and sapwood area predispose emergence from the grass stage. Two longleaf pine seed sources were grown in two types of commercial container cavities and 20 seedlings of each treatment combination were transplanted into 22.5 L pots (27 cm diameter, 50 cm tall) containing commercial potting mix. Potted seedlings were randomly placed on benches in a greenhouse and grown for 52 weeks under ambient environmental conditions. Nine months after potting, 0%, 6%, 25%, or 64% of seedlings in the four treatment combinations had emerged from the grass stage. Seedlings will be destructively harvested in November 2020 and relationships between emergence from the grass stage and root system, stem, and shoot variables will be evaluated. Knowledge of morphological relationships linked with emergence from the grass stage will provide insight about how seedling culture and planting environment influence longleaf pine height growth initiation and juvenile growth. Prescribed fire has become the primary tool for maintaining the longleaf pine (Pinus palustris Mill.) ecosystem. Traditionally, burning occurs in the dormant season to help limit fire intensity and reduce the risk of overstory tree mortality. However, in some locations, the recent expansion in longleaf pine acreage has outpaced local capacity for dormant season burning necessitating the adoption of new burning strategies or alternative methods for maintaining woodland structure. While burning outside the dormant season, using alternative understory treatments, or using a combination of treatments may increase local management capacity, little is known about the long-term effects of these methods on longleaf pine productivity. To explore this issue, we established a fully crossed factorial experiment examining the effects of bi-annual seasonal burning (dormant season, summer, spring, none) and alternative understory treatments (mechanical, chemical (2,4-D and glyphosate), none) on longleaf pine diameter, height, and volume growth over 23 years at the Escambia Experimental Forest in Brewton, Alabama. Overall, mean diameter and volume growth of longleaf pine was maximized in plots treated with only chemical applications (7.9 cm and 0.4 m3). Longleaf pine height growth was maximized in plots receiving bi-annual mechanical treatments and summer burning (3.7 m). However, no statistically significant differences were detected among treatments for any growth response metric. Collectively, our results demonstrate that burning outside the dormant season or using chemical or mechanical understory treatments will have minimal effects on longleaf pine productivity.
A research prospectus: effects of canopy gaps created by Hurricane Michael on longleaf pine regeneration and community reorganization. C. Pope, Graduate Student, Jones Center at Ichauway, Newton, GA S. Bigelow, Researcher, Jones Center at Ichauway, Newton, GA A. Sharma, Researcher, University of Florida, Milton, FL J. Cannon, Researcher, Jones Center at Ichauway, Newton, GA
Understanding wind risk to forests: Towards mechanistic models of wind risk in the southeastern Coastal Plain. J. Cannon, Forest Management Scientist, Jones Center at Ichauway, Newton, GA B. Rutledge, Conservation Coordinator, Jones Center at Ichauway, Newton, GA K. McIntyre, Education Coordinator, Jones Center at Ichauway, Newton, GA A. Holland, Postdoctoral Associate, University of Delaware, Newark, DE S. Jack, Executive Director, Boggy Slough Conservation Area, T.L.L. Temple Foundation, Lufkin, TX
Longleaf pine (Pinus palustris) forest reorganization following a catastrophic windstorm is dependent upon the size of canopy gaps formed, abundance and size of advanced regeneration present, as well as their response to increased resource availability. Studies suggest that longleaf pine exhibit an advantageous height growth response compared to competing hardwoods under large canopy openings, but little is known about the mechanisms governing community reorganization under smaller canopy gaps. In October 2018, a category-5 hurricane made landfall and traveled northwest across the state of Georgia, causing widespread damage. Two years later, the gaps created by the storm allowed for an opportunity to examine longleaf pine regeneration and community responses to the disturbance. To better understand oak mesophication and identify possible feedbacks, we are investigating growth of regenerating longleaf pines and competing oak species (Quercus falcata & Q. margarettae) across a gradient of soil moisture under varying canopy densities in southwest Georgia. Using dendrochronological approaches and stand measurements, we are determining past and current growing conditions of the longleaf pine communities, in addition to measuring light availability and soil characteristics. Under intermediate sized canopy openings, we expect the height growth response of competing longleaf pines and oak species to shift depending upon soil water holding capacity. Also, we expect that longleaf pine will respond more positively to light suppression relief in drier sites when compared to both oak species. Understanding patterns of reorganization following disturbances can inform land management in a climate where severe storms are expected to become more frequent. Severe storms such as hurricanes alter the structure and function of forests, and add risk and uncertainty to the management of important forest ecosystems of the southeast. However, there is little information to provide guidance to help mitigate wind risk. Longleaf pine is often ranked among the most wind-resistant species of the southeastern coastal plain, but differences in size structure and association of species with varying soil types obscures a clear understanding of wind susceptibility among southeastern species. Factors such as stand density, soil type, elevation, and topographic position also affect damage severity and further confound tree-level differences. Using observations from over 3,000 trees exposed to Hurricane Michael, we investigated how tree-level factors (species and size), stand-level factors (stand density and soil type) and landscape-level factors (wind exposure and landscape configuration) affect tree vulnerability to hurricane winds while accounting for differences in size and spatial structure inherent to natural forest populations. Probability of damage varied between species, was dependent on soil type, and increased with increasing size for most species. Generally, pine susceptibility increased in poorly drained soils, while oak susceptibility increased in well drained soils. Longleaf pine showed the lowest variability in wind susceptibility across soil types and was in the lower damage probability range for all soil types. Borrowing from wildfire-risk modeling, we introduce a framework for assessing wind-risk for southeastern forests that combines mechanisms at several scales. Such hierarchical models can be critical for quantifying wind-risk and guiding management of southeastern landscapes.
Percentage of trees bearing cones as a predictor for annual longleaf-pine cone production.
T. Patterson, Assistant Professor, The University of Southern Mississippi, Hattiesburg, MS
Tree size, stand density, and crown position influence a hurricane’s damage to planted longleaf pines. S. Bigelow, Assistant Scientist, Forest Ecology, The Jones Center at Ichauway, Newton, GA
A. Whelan, Research Associate, The Jones Center at Ichauway, Newton GA J. Cannon, Assistant Scientist, Forest Management, The Jones Center at Ichauway, Newton, GA G. Starr, Professor, University of Alabama, Tuscaloosa, AL C. Staudhammer, Professor, University of Alabama, Tuscaloosa, AL G. Kenney, Graduate Research Associate, University of Alabama, Tuscaloosa, AL
Annual longleaf-pine cone production has been measured by the USFS and its affiliates at various sites throughout the southeastern US beginning in 1958. Data from these annual surveys are provided to the public as a regional estimate for cone production, and have been used to examine relationships between cone production and climate, stand dynamics, and tree-ring growth. The method for surveying cones involves counting the exact number of cones per tree for a predetermined number of trees at each site. As an alternative approach, I am reporting on a rapid assessment that calculates the percentage of trees bearing cones using a binary (yes/no) measurement of cone production. I was permitted access to an individual-tree cone production dataset that contained 234 trees from 18 sites spanning 29 years. I examined the relationship between the percentage of trees bearing cones (PBC) at each site to log-transformed cone counts using simple linear models. PBC explained 56-94% of the variance in log-transformed cone counts (R2 values ranged 0.56-0.94, avg. = 0.80, SD = 0.11). When PBC > 90%, average cones per tree was 65.8; however, cones per tree quickly diminished below 30 when PBC was 70% and was considered failed (< 10 cones per tree) when PBC < 50%. While PBC cannot replace the multidecadal USFS cone measuring system, it can be used as an alternative approach when a rapid measure is needed. Planting restores fragmented longleaf pine woodland of the southeastern coastal plain, but stands are vulnerable to wind. We measured trees in 1/10 acre plots in 80 planted stands in Florida and Georgia after Hurricane Michael. Estimated wind gusts varied from 30 to 80 m s-1, and proportion of intact stems varied from 0% to 100%. Variables such as height, diameter-to-height ratio, and depth to B horizon did not explain a significant amount of survival. There was a 17% decrease in survival with each 10 m s-1 increase in estimated gust speed. At constant wind speed there was a slight decrease in damage for larger trees, but as wind speeds increased larger trees were much more likely to be damaged. Trees that were smaller than the average size in a plot were more likely to be damaged, and denser stands suffered slightly less damage. Our results show that even for the highly wind-firm longleaf pine there is risk of loss of significant portions of stands due to hurricane winds, and that the risk increases with proximity to the coast. The vulnerability of trees with lower crown positions suggests the importance of regular thinning although this suggestion is at odds with lower damage in denser stands. A bet-hedging strategy of mitigating damage risk by staggering thinnings in time is advisable. Ultimately, better understanding of wind-throw risk will increase knowledge of costs and benefits of longleaf pine ecosystem restoration.
Wednesday, March 17, 2021 10:00-12:00 CONCURRENT SESSIONS
SESSION 5: A, B
SESSION 5B – Upland Hardwoods Management I
Natural pruning varying with sweetgum variety and density.
J. Adams, Associate Professor, Louisiana Tech University, Ruston, LA M. Blazier, Professor, Louisiana State University AgCenter Hill Farm Research Station & School of Renewable Natural Resources, Homer, LA
A sweetgum (Liquidambar spp.) study was installed at two sites in Louisiana in the winter of 2015-2016. Two taxa were planted: native sweetgum, L. styraciflua, and a hybrid, L. styraciflua x formosana. Planting was done in 25-tree block plots, and trees have been measured for diameter and height each year since planting. Crown closure appeared to begin during the fourth year in blocks with near-complete survival. By mid-growing season of that year, some blocks of the faster-growing hybrids began to both exhibit complete crown closure and begin the natural pruning process. We will explore the genetic and stocking effects on natural pruning. Overall the hybrids grew faster and thus had a greater stocking than the native counterparts. The varying densities presented by the suite of hardwood genotypes presents a novel look at the densities needed to stimulate limb fall.
C. VanderSchaaf, Assistant Professor, Louisiana Tech University, Ruston, LA
Twenty-eight Years of Cooperative Oak Research and Technology Development in the Southern Regions.
S. Clark, Research Forester, USDA Forest Service Southern Research Station, Knoxville, TN S. Schlarblaum, Professor, University of Tennessee, Knoxville, TN B. Crane, Regional Geneticist (Retired), USDA Forest Service Southern Region, Atlanta, GA
In 1992, a long-term partnership was initiated among the University of Tennessee’s Tree Improvement Program (UT-TIP), and the Southern Region, Genetic Resources Program (Region 8) and Southern Research Station (SRS) of the USDA Forest Service for the purpose of developing successful artificial regeneration protocols for oak species using high-quality, pedigreed seedlings for restoration and enrichment of the oak component in southern Appalachian forests. The majority of previous research and technology with oak species had been developed in the Central and Northeastern States on sites generally devoid of fast-growing competition like tulip-poplar (Liriodendron tulipifera), and seedlings used in plantings were relatively small in size from unpedigreed sources. A 1993 bumper acorn crop in the Watauga Seed Orchard of the Cherokee National Forest vitalized a largescale project to establish progeny tests and seed production areas across Region 8. The partnership has evolved to test high-quality improved seedlings across various silvicultural settings and to further refine nursery protocols for using pedigreed oak seed. Additional research and technology has been developed with the goal of providing recommendations on oak seed orchard management, characterizing seedlings, selecting acorn sizes for sowing, efficacy of seed storage, and effects of top pruning on seedling quality.
Potential impacts of forest ecosystem restoration on water yield at Ocala National Forest.
I. Ojo, Research Assistant, University of Florida, Immokalee, FL L. Ngatia, Assistant Professor and Soil Biogeochemist, Center for Water Resources, Tallahassee, FL C. Oishi, Research Ecologist and Science Team Leader, USDA Forest Service Southern Research Station Coweeta Hydrologic Laboratory, Coweeta, NC J. Grace, General Engineer & FFWRP Program Manager/Coordination Lead, USDA Forest Service, Center for Forest Watershed Research, Southern Research Station, Tallahassee, FL A. Lorenzo, Professor, Florida A&M University College of Food Agriculture and Food Sciences, Tallahassee, FL
Legacy effects of past harvesting on woody understory structure and composition in contemporary deciduous broadleaved forests of the southern Appalachian Mountains
T. Keyser, Project Leader and Research Forester, USDA Forest Service Southern Research Station, Asheville, NC J. Rodrigue, Forest Silviculturalist, USDA Forest Service, Asheville, NC
Watershed management can have a significant influence on water quantity and quality, and habitat restoration efforts can have significant effects on groundwater resources. Tree- and stand-level transpiration was estimated in two stands: a mature sand pine (Pinus clausa) plantation and a restored scrub-oak stand. Results showed some significant differences in species unit transpiration and drought tolerance. Under optimum conditions, estimated average sap flux density was similar among 3 oak species, within and among the two sites (167 g H2O cm-2 sapwood day-1 for myrtle oak (Quercus myrtifolia), sand live oak (Quercus geminata), chapman oak (Quercus chapmanii)) while sand pine, was significantly lower (78 g H2O cm-2 sapwood day-1). Stem diameter at breast height (DBH) averaged 17.4 cm for sand pines, while the chapman, sand live, and myrtle oaks were 3.9, 6.8, and 8.6 cm in average DBH, respectively. Average tree-level water use under optimal conditions at the sand pine site was 4.71 kg day-1, 1.38 kg day-1 and 6.30 kg day-1 for sand pine, chapman oak and myrtle oak respectively, while whole-tree water use at the oakscrub site was 6.66 kg day-1, 3.86 kg day-1 and 1.22 kg day-1 for myrtle oak, sand live oak, and chapman oak, respectively. Under limiting soil moisture conditions, sand pine, sand live oak, and myrtle oak showed approximately 24%, 29%, and 43% reduction in transpiration, respectively, while chapman oak showed no change with water stress. Although average tree size was higher for the pine site than the oak-scrub site, stem density was much lower. High stem density in the oak-scrub site resulted in significantly higher canopy interception of precipitation than in the sand pine stand. Compared to the pine plantation, the oak-scrub site had higher transpiration (301 mm versus 214 mm) and higher interception (455 versus 147 mm) over the 10 month study period.
Yellow-poplar (Liriodendron tulipifera L.) is the most abundant individual tree species (in terms of volume) in the Blue Ridge (M221D) ecological subsection of the southern Appalachian Mountains, with forest inventories documenting a continuous increase of this species over the recent years. As a consequence of a shift in management objectives, previously thinned stands originally managed on a timber-or financially-related rotation length are no longer actively managed within the original silvicultural prescription. Limited quantitative data exists regarding the effects of previous management activities on stand dynamics, including the effects of thinning on the diversity and composition of the regeneration layer in productive yellow-poplar stands. Understanding the response of the understory is particularly important in pure yellow-poplar stands, as restoration efforts include increasing ecological complexity, including species diversity, in these systems. In 1960 a long-term study examining the growth and yield of thinned yellow-poplar as a function of age, site quality, and residual density was established by scientists at Bent Creek Experimental Forest. A total of 141 0.1-ha plots were established in yellow-poplar stands throughout the southern Appalachians in North Carolina, Tennessee, Georgia, and Virginia. Plots were established in a manner that encompassed a broad range of site productivities, as defined by site index, and stand ages. After establishment, plots were thinned to varying levels of residual density. In 2018, we revisited 66 of the original 141 plots located in North Carolina in efforts to (1) quantify current overstory structure and (2) assess how the original thinning prescription, conducted across age and site quality gradients, affected the development of the arborescent regeneration layer. Effects of past thinning prescriptions on species composition and functional identity of the regeneration layer and implications related to management and restoration objectives in pure yellow-poplar forests are discussed.
Long-term effects of alternative partial harvesting methods on the woody regeneration layer in high-elevation Quercus rubra forests of the southern Appalachian Mountains, USA
T. Keyser, Project Leader and Research Forester, USDA Forest Service Southern Research Station, Asheville, NC D. Loftis, Research Forester (Emeritus), USDA Forest Service Southern Research Station, Asheville, NC
Effects of long-term forest management on mercury bioaccumulation in aquatic food webs.
P. Ku, Postdoctoral Fellow, Oakridge National Laboratory, Oak Ridge, TN M. Tsui, Associate Professor, University of Noeth Carolina at Greensboro, Greensboro, NC T. Farmer, Assistant Professor, Clemson University, Clemson, SC D. Amatya, Research Hydrologist, USDA Forest Service, Cordesville, SC C. Trettin, Team Leader and Supervisor, Research Soil Scientist, USDA Forest Service, Cordesville, SC A. Chow, Associate Professor, Clemson University, Georgetown, SC
High-elevation deciduous broadleaved forests in the southern and central Appalachian Mountains of the eastern United States represent a transition zone between temperate mixed-Quercus forests that dominate lower elevations and remnant Picea-Abies evergreen forests found at high elevations. Along with northern hardwood and Picea-Abies forests, high-elevation Q. rubra forests, which occupy approximately 70,110 ha in the southeastern US are one of three principle high-elevation cover types in the southern Appalachians. The juxtaposition of high-elevation Q. rubra forests with other high-elevation forest types means these forests often provide and maintain critical wildlife habitat for a variety of bird and mammal species that are reliant on other, higher elevation habitats. In montane Quercus forests of the southern Appalachians, competition from a suite of predominantly shade-intolerant species (e.g., Betula lenta and Liriodendron tulipifera) following canopy disturbance is the primary cause of Quercus regeneration and recruitment failure. Environmental conditions associated with high-elevation Q. rubra forests limit the abundance and competitiveness of competitor species (L. tulipifera, in particular); a factor which may alter regeneration dynamics and improve Quercus regeneration outcomes following canopy disturbance. In 1994, a large-scale collaborative study examining regeneration dynamics of high-elevation Q. rubra forests following overstory canopy manipulation was initiated on the Nantahala National Forest in western North Carolina. A total of 11, high-elevation Q. rubra stands were identified, and each stand was randomly assigned to one of four treatments: (1) control (n=2); (2) group selection (n=3); (3) Irregular shelterwood with high residual basal area (n=3); and (4) irregular shelterwood with low residual basal area (n=3). We sampled the arborescent regeneration layer prior to harvest and again at 4, 8, and 22 years post-harvest. Effects of regeneration treatments on species composition and implications related to management and restoration objectives in high-elevation Q. rubra forests are discussed. Land use changes and forest management practices (e.g., prescribed burn, mechanical thinning, etc.) are known to alter ecosystem structure and water quality. However, little is known about its short- and long-term impacts on the biogeochemical cycling of mercury (Hg), a global pollutant which can be bioaccumulated and biomagnified in natural food webs, posing a concern to the health of top predators. The present study is aimed to understand the impacts of forest management on Hg bioaccumulation in aquatic food webs. A paired watershed of similar size (~150-160 ha) (unmanaged WS80 vs. managed WS77) located at the USFS Santee Experimental Forest on the Atlantic coastal plain of South Carolina has been studied for Hg bioaccumulation in aquatic food webs after longterm forest management on WS77. We examined methylmercury (MeHg) in stream biota in both watersheds, including biofilm, macroinvertebrates, and fish, as well as streamwater (biweekly sampling). We observed much higher MeHg levels in both mosquito fish (~4 folds) and dollar sunfish (~2 folds) in WS77 than those in WS80, with similar trends in macroinvertebrates (crayfish, dragonfly larvae, water scorpions etc.), but we found no difference in MeHg levels in streamwater and biofilm samples among the paired watershed. The higher MeHg contents in fish and macroinvertebrates may be attributed to the different food web structure and organismal growth rate. This study provides new insights into how forest management affects Hg bioavailability and bioaccumulation in the aquatic environment.
Biomass production of eastern cottonwood (Populus deltoids Bartr. Ex Marsh) and black willow (Salix nigra Marsh.) in the Lower Mississippi Alluvial Valley.
B. Dahal, Graduate Research Assistant, Mississippi State University Department of Forestry, Starkville, MS K. Poudel, Assistant Professor, Mississippi State University Department of Forestry, Starkville, MS
Eastern cottonwood and black willow are short rotation woody crops (SRWCs) native to Lower Mississippi Alluvial Valley with high biomass production potential under short rotation. The plantation of SRWCs has accelerated in the United States and across Europe with the increasing demand of wood energy. However, the best management system to maximize biomass production and ensure sustainable supply of energy remain unidentified. This study assesses the biomass production of eastern cottonwood and black willow in four planting densities (3x3ft, 7x2.5ft, 9x6ft and 12x12ft) and four harvest frequencies (harvest at every 2, 3, 4 and 6 year). The experimental design used is split plot experiment in randomized complete block design with three replicate blocks. The plantation site was previously an agricultural field with rice cultivation where Sevin was aerial sprayed to protect cottonwood from leaf beetle. During the harvest year, the diameter at breast height (DBH), height and green weight of the dominant stem from each tree is measured. Preliminary results showed difference in biomass production among different spacing and production regimes in both of the species. These results will provide insights into the biomass potential and help make better management decisions for the sustainable bioenergy production from SRWCs.
H. Renninger, Assistant Professor, Mississippi State University Department of Forestry, Starkville, MS J. Granger, Assistant Professor, Mississippi State University Department of Forestry, Starkville, MS T. Leininger, Project Leader, USDA Forest Service Southern Research Station Center for Bottomland Hardwood Research, Stoneville, MS E. Gardiner, Research Forester, USDA Forest Service Southern Research Station Center for Bottomland Hardwood Research, Stoneville, MS
Impacts of Microstegium vimineum on seedling growth and survival of three common hardwood species under different light and moisture levels. C. Goldsmith, Graduate Research Assistant, Mississippi State University Department of Forestry, Starkville, MS H. Alexander, Assistant Professor, Auburn University, Auburn, AL J. Granger, Assistant Professor, Mississippi State University Department of Forestry, Starkville, MS C. Siegert, Associate Professor, Mississippi State University Department of Forestry, Starkville, MS
Limited natural oak regeneration in current closed-canopy forests has evoked substantial research investigating the use of various silvicultural practices to restore and/or maintain upland oak forests. However, through disturbance many of these practices have the potential to promote the spread of invasive species, such as Japanese stiltgrass (Microstegium vimineum (Trin.) Camus). Microstegium vimineum establishes across various forest conditions due to its plasticity, creating dense understory cover that exacerbates management complications of oak seedling recruitment. To evaluate the effects of M. vimineum presence on forest regeneration, we established a shadehouse experiment with a completely randomized split-split-split plot design with of one-year old white oak (Quercus alba), red maple (Acer rubrum), and sweetgum (Liquidambar styraciflua) seedlings in the following treatments: Microstegium presence (with/without), light environment (60/90% shade), moisture environment (wet/dry), and their interactions. Measurements were taken from May-October by documenting weekly soil moisture and monthly M. vimineum percent cover and height and seedling basal diameter, stem height, annual growth, and survival. All tree species planted with M. vimineum were significantly smaller than the seedlings without M. vimineum regardless of environmental conditions. White oak basal diameter with M. vimineum was 53% lower compared to those without M. vimineum, but annual growth did not differ. In contrast, both red maple and sweetgum had smaller basal diameters (40 and 38%, respectively) and annual growth (62 and 37%, respectively) in the presence of M. vimineum. These results indicate that the invasion of M. vimineum in forest communities may reduce seedling recruitment, further complicating oak regeneration.
Wednesday, March 17, 2021 1:00-3:00 CONCURRENT SESSIONS
SESSION 6: A, B
SESSION 6A – Shortleaf Pine Management
Shortleaf pine sprouting and pine competitive status during the first growing season after prescribed burning in a Mid-Atlantic mixedwood forest M. Olson, Assistant Professor, Stockton University, Galloway, NJ
Analyzing 62 year data on shortleaf pine trees in common garden experiment.
G. Gallagher, Student, Stockton University, Lawrenceville, NJ M. Olson, Assistant Professor, Stockton University, Galloway, NJ
Intraspecific competition increases growth of enrichment-planted shortleaf pine seedlings in a mixed-hardwood clearcut on a xeric site after 13 years in the southern Appalachians.
H. McNab, Research Forester, USDA Forest Service Southern Research Station, Asheville, NC
A prescribed burn in March 2020 created an opportunity to assess fire effects on natural pine reproduction in a coastal plain pine-hardwood forest. The study site is a natural canopy gap located on public land in the western edge of the New Jersey Pine Barrens. The pine component is a mixture of shortleaf pine and Virginia pine. The size, fire damage, and competitive status of natural pine reproduction was assessed shortly after the burn. A total of 36 shortleaf pine seedlings were tagged for monitoring basal-crook sprouting and competitive status during the 2020 growing season. All tagged shortleaf pine seedlings survived to end of the first season: 29 via basal-crook sprouting, 2 via resistance to topkill, and 5 through a combination of sprouting and resistance. By contrast, all four Virginia pines seedlings accidentally tagged as shortleaf were killed by fire. This result suggests that prescribed burning can be used to favor shortleaf pine reproduction over Virginia pine, similar to what has been observed in loblolly-shortleaf pine mixtures in Arkansas and Oklahoma. The dynamics of shortleaf pine sprouting will be presented and discussed along with changes in competitive status of pine reproduction in this hardwood-pine gap cohort. In 1958, a shortleaf pine (Pinus echinata) common-garden experiment was established at a single planting site in Green Bank, New Jersey. This planting was established as part of a much larger range-wide effort evaluating geographic variation of shortleaf pine and several other southern pine species. The original design included planting 2-year-old bare-root seedlings grown from seed collected from seven different locations, including: New Jersey, Virginia, South Carolina Georgia, Tennessee, Missouri, and Louisiana. Experimental units are contiguous blocks of 49 measurement specimens of each seed source. The current investigation focuses on the survival, growth, and development in the 62nd-year of the shortleaf pine common-garden experiment at Green Bank. Data collection occurred in summer of 2020 and consisted of estimating the stem diameter (DBH) and top height of all surviving measurement trees. Data was submitted to analysis of variance for a randomized block design. Additionally, regression analysis was used to explore geographic variation in long-term survival, tree diameter, and tree height. These results will be presented along with implications for management and conservation. Shortleaf pine (Pinus echinata) can be a minor component of mixed-hardwood communities on low-elevation, xeric sites in the southern Appalachian Mountains, but its reproduction is not being recruited to replace mature trees lost to natural causes. Enrichment planting is one method to regenerate pines for restoration of biodiversity. Previous inventory of enrichment plantings of shortleaf pines revealed low overall pine survival (12.5%). Survival of dominant and codominant pines, however, appeared to occur in groups of two or more crown-touching trees; not single trees. I tested the hypothesis that intraspecific competition among neighboring pines would result in better growing conditions (less overtopping by hardwoods, resulting in larger trees) compared to interspecific competition between single pine trees and surrounding hardwoods. I inventoried dbh of all surviving shortleaf pines in two, 0.2 ha sample sites individually and by groups of +2 crown-touching trees. I learned that pines occurring in groups of +2 trees were significantly (p < 0.002) larger in dbh (8.2 cm) compared to singly occurring trees (5.3 cm). Equivalent predicted heights were 8.0 m and 5.3 m, respectively. Grouped pines were typically in codominant or dominant crown classes, but single pines were usually in suppressed or intermediate classes. These results suggest that economics of tree seedling and labor costs and biodiversity restoration results could be improved if enrichment plantings of shortleaf pine seedlings in small clearcuts are established in scattered groups of 5 or more closely spaced trees rather than widely separated individuals in conventional rows.
Restoration of conifers to a xeric oak ridge site by clearcutting and planting shortleaf and pitch pines - lessons learned after 13 years
H. McNab, Research Forester, USDA Forest Service Southern Research Station, Asheville, NC
Early growth and survival of bareroot loblolly pine (Pinus taeda), bareroot shortleaf pine (Pinus echinata), and containerized shortleaf pine in central Mississippi. S. Madden, Graduate Research Assistant, Mississippi State University Department of Forestry, Starkville, MS H. Renninger, Assistant Professor, Mississippi State University Department of Forestry, Starkville, MS A. Self, Associate Extension Professor, Mississippi State University Extension, Grenada, MS A. Ezell, Professor Emeritus, Mississippi State University, Starkville, MS J. Granger, Assistant Professor, Mississippi State University Department of Forestry, Starkville, MS
Yellow pines (Pinus echinata and P. rigida) are not regenerating in formerly mixed oak pine stands on low elevation mountain ridges in the Southern Appalachians where fire has been excluded, resulting in loss of biodiversity. The objective of this study was to evaluate planting as a method for restoring pines to a xeric, southwest-facing ridge site following clearcutting of the mature mixed oak (Quercus montana, Q. coccinea) overstory. Preharvest stand basal area averaged 27 m2/ha, distributed as shortleaf pine 1%, oaks 66%; red maple 14% and other 19%. One year after conventional site preparation by chainsaw felling of residuals, 1-0 bare-root seedlings of either shortleaf or pitch pine seedlings were bar planted at 1.8 m x 2.5 m spacing (2,222/ha) in four, 0.15 ha plots. When the pine seedlings were released from hardwood competition by thinline herbicide treatment at 3 years, survival of both species was high, > 95%. At 13 years, overtopping by hardwoods had reduced the density of pines to about 200/ha. There was no difference between pine species for survival or basal area. Mean stand basal area at 13 years was 22 m2/ha, distributed as pines 13%, oaks 36%, red maple 2%, yellow-poplar 38% and other 11%. Most surprising was the high stem density of yellow-poplar in the regenerated stand, which were absent before harvest. The objective of this restoration project was to re-establish a small component of yellow pines in the stand, which was accomplished. Yellow-poplar will probably maintain its codominance in the stand. Bareroot loblolly pine (Pinus taeda), bareroot shortleaf pine (Pinus echinata), and containerized shortleaf pine were planted in February 2020 on the John W. Starr Memorial Forest in northeast Mississippi using three replications of completely randomized design with 100 seedlings of each treatment in each replication. A total of three hundred seedlings of each treatment were planted, with 900 seedlings utilized in this study. The purpose of the study was to compare first-year growth and survival between the industry standard (bareroot loblolly pine) and planting stocks of shortleaf pine. Monthly survival was recorded through the first growing season. After one growing season, bareroot loblolly pine exhibited the greatest survival (99%) followed by containerized shortleaf pine (98%), with bareroot shortleaf having less than desirable survival (61%). Average height growth of bareroot loblolly was also greater (26.1 centimeters) than bareroot shortleaf (11.1 centimeters) or containerized shortleaf (8.1 centimeters). Average groundline diameter growth of bareroot loblolly (5.0 millimeters) was also greater than bareroot shortleaf (3.5 millimeters) or containerized shortleaf (2.7 millimeters).
Radial growth response of shortleaf pine (Pinus echinata) and post oak (Quercus stellata) to climatic variability and management in southeastern Oklahoma. R. Will, Professor, Oklahoma State University, Stillwater, OK A. Adhikari, Post Doc, Oklahoma State University, Stillwater, OK R. Masters, Retired, University of Wisconsin – Stevens Point, Stevens Point, WI H. Adams, Assistant Professor, Washington State University, Pullman, WA O. Joshi, Assistant Professor, Oklahoma State University, Stillwater, OK
We investigated the radial growth response of shortleaf pine (Pinus echinata) (~24 cm average dbh) and post oak (Quercus stellata) (~ 36 cm average dbh) to climatic variation and management using tree cores collected in southeastern Oklahoma near the drier, western limit of their ranges. Beginning in 1984, experimental units were created by combinations of pine harvest, hardwood thinning, and fire return intervals (1, 2, 3, 4 years and none) that produced ecosystems ranging from closed-canopy forest to savanna. Weather for previous- and current-year, and years since fire were used to determine the relationship between radial growth and climate variability (1987 - 2018) for different management regimes. Shortleaf pine growth increased with growing season precipitation, decreased with average summer temperature maximum, and increased with previous year’s average October minimum temperature. Radial growth of shortleaf pine decreased by ~25% the first year after prescribed fire for 2- and 3-year fire return intervals. Suppressed shortleaf pine were less responsive to climate variability than intermediate or co-dominant trees. Shortleaf pine growing in savannas appeared less sensitive to annual variation in precipitation. Post oak radial growth was most responsive to water availability during May-July the previous year. Burning regime and stand density did not influence the response of post oak radial growth to climate variability. Overall, a drier climate with hotter summers will likely reduce the growth of shortleaf pine and post oak in southeastern Oklahoma. Management for lower stand density may dampen variation to climatic variability for shortleaf pine, but not post oak.
C. Zou, Professor, Oklahoma State University, Stillwater, OK
Wednesday, March 17, 2021 1:00-3:00 CONCURRENT SESSIONS
SESSION 6: A, B
SESSION 6B – Upland Hardwoods Management II
Preferential herbivory by cottontail rabbits (Syvilagus floridanus) in planted oak seedlings.
S. Madden, Graduate Research Assistant, Mississippi State University Department of Forestry, Starkville MS H. Renninger, Assistant Professor, Mississippi State University Department of Forestry, Starkville MS A. Self, Associate Extension Professor, Mississippi State University Extension, Grenada, MS A. Ezell, Professor Emeritus, Mississippi State University, Starkville, MS J. Granger, Assistant Professor, Mississippi State University Department of Forestry, Starkville, MS
Nuttall oak (Quercus texana) and swamp chestnut oak (Quercus michauxii) seedlings were planted in 2019 to compare survival and growth between bareroot and containerized planting stocks. In June 2019, damage and mortality caused by cottontail rabbits (Syvilagus floridanus) was observed. Data on how many seedlings of each species/planting stock were impacted by rabbits were recorded monthly from June through October. Little is known about the preferences of rabbits for which oak species or group they target, but in this study rabbits caused substantial mortality to bareroot Nuttall oak seedlings. Thirty-two percent of all seedling mortality on the site was attributed to rabbits, with 82 percent of all bareroot Nuttall oak seedling mortality coming from their damage.
Fifth year development of natural regeneration following pre-commercial herbicide release treatments. S. Peairs, Assistant Professor Extension Specialist for Forest Management, Clemson Extension Service, Clemson SC
W. Clatterbuck, Professor, UNiersity of Tennessee, Knoxville TN
Understory invasion by Microstegium vimineum in a closed-canopy oak forest leads to high mortality of white and Shumard oak seedlings. H. Alexander, Assistant Professor, Auburn University, Auburn, AL
C. Goldsmith, Graduate Research Assistant, Mississippi State University Department of Forestry, Starkville, MS J. McDaniel, PhD Student, University of Georgia, Athens, GA R. Nation, Undergraduate Researcher, Mississippi State University, Starkville, MS A. Paulson, Post-Doctoral Research Associate, University of California Davis, Davis, CA
Land managers have a challenging time attempting to maintain the competitive status of oak reproduction following clearcutting. Early herbicide applications have the potential to assist oak reproduction in reaching competitive status at crown closure. Yellow-poplar, red oak, and white oak trees were re-measured for change in height and ground line diameter five growing seasons following early herbicide applications conducted concisely after clearcutting. Prior treatments around the trees included radial sprays using glyphosate, post-emergent release with sulfometuron methyl, and untreated control. Though 2-year growth responses were statistically different between treatments, after five years no difference existed between the herbicide treatments and control. Findings from this study suggest that additional competition sources will rapidly invade bare ground around favored reproduction gained from chemical plant control. Ultimately, any growth gains associated from the herbicide applications are likely restricted to the first couple of growing seasons. The early seedling growth gains yielded from the early release treatment may assist in promoting early oak establishment but may not be enough to ensure oak reach dominant crown positions at crown closure. Thus, additional silvicultural management such as crop tree release is warranted to reach this objective. Upland oaks (Quercus spp.) in the eastern U.S. often fail to recruit into the canopy in the absence of disturbances like fire that clear the understory and increase light penetration. Because oaks are mast producers and premier hardwoods, managers are increasingly implementing prescribed fire to reduce competition from fire-intolerant competitors and improve growing conditions for regenerating oaks. However, concern over fire’s potential to increase invasion by the exotic grass Japanese stiltgrass (Microstegium vimineum) has caused some managers to question the benefits versus costs of prescribed fire application in forests susceptible to this invader. To better understand stiltgrass invasion impacts on regenerating oak seedlings, we grew white (Q. alba) and Shumard (Q. shumardii) oak seedlings from acorns in a greenhouse and subsequently planted them in a common garden experiment with varying stiltgrass invasion (0, 50, and 100% cover) beneath a closed-canopy upland oak forest in north Mississippi in May 2019. We randomly assigned half of the Shumard oak seedlings to seedling shelter tube treatments to determine if exposure to deer browse influenced susceptibility to stiltgrass invasion. We found that seedlings planted into stiltgrass (regardless of cover or tube treatment) experienced > 85% mortality by September 2019, with < 20% mortality of those without invasion. Given that seedlings were always taller than the surrounding stiltgrass, the mechanism for seedling mortality does not appear to be aboveground competition for light. These findings confirm that stiltgrass invasion is detrimental to oak regeneration at least during the seedling stage in low light environments.
Is there hope for hybrid poplars in the southern United States
K Smith, Research Associate, Mississippi State University Department of Forestry, Starkville, MS R Rousseau, Extension/Research Professor (Retired), Mississippi State University Department of Forestry, Paducah KY M Murphy, Research Associate, Mississippi State University Department of Forestry, Starkville, MS
Water use and efficiency of eastern cottonwood and hybrid poplars grown on contrasting sites in the Southeastern U.S
H Renninger, Assistant Professor, Department of Forestry, Mississippi State University, Starkville, MS L Stewart, Graduate Student, Mississippi State University, Starkville MS R Rousseau, Extension/Research Professor, Mississippi State University, Starkville, MS
Many people don’t realize that hybrid poplars were ever considered for deployment in the Lower Mississippi River Valley (LMAV). This effort was initiated in the mid-1980s, with tests of clonal material recommended by the University of Washington in concert with eastern cottonwood clone tests. The reasoning behind this effort was an attempt to determine if the hybrid vigor that observed in the Pacific Northwest could be captured on sites in the LMAV. Early-age results showed promise with higher survival rates than eastern cottonwood and rapid growth rates that rivaled that of eastern cottonwood when grown on the newly developing and highly fertile soils of Mississippi River Valley. Unfortunately, what was also discovered was the unknown Achilles heel of these hybrids and that was their susceptibility to Sphaerulina musiva, also known as Septoria musiva. This fungus is both a leaf disease as well as a canker disease that manifest itself on both stem and limbs of hybrid poplars. It is the stem cankers that results in mortality of the hybrids. Although eastern cottonwood is not resistant to the leaf spot disease of the fungus, it is resistant to the canker formation. In 2010, 2011, and 2013 another series of tests established by Mississippi State University included both selected eastern cottonwood and hybrid poplars genotypes on alluvial sites. These tests verified what had been observed by researchers at Westvaco, where mortality of the most susceptible hybrid genotypes fell prey early on (i.e. 4 to 5 years) and that by age 10 not a single hybrid genotype was surviving. Like the earlier tests the eastern cottonwood genotypes exhibited no signs of canker and maintained excellent growth rates. However, these new tests also included an upland companion site outside of the LMAV. These sites revealed a different story in that a limited number of hybrid clones exhibited higher survival rates, thus providing a glimmer of hope in the possibility of finding selected resistant hybrid genotypes. In addition, other examinations under the Integrated Biomass Supply System (IBSS) also indicated that this is probably the correct assumption. In 2018, under the Advancement of Populus Pathways in the South (APPS), one of the major goals was to test a greatly expanded number of hybrid poplar clones outside of the LMAV. To date, approximately 200 new hybrid poplar clones of varying taxa have been established in test since 2018 under the APPS project. Early results and procedures from these tests will be presented. Short rotation woody crops including eastern cottonwoods and hybrid poplars have the potential for fast growth making them attractive bioenergy crops. However, total water use and water use per unit biomass produced (water use efficiency; WUE) of various Populus varietals are important to ensure that crops do not impact surrounding hydrology. Likewise, determining the environmental drivers of water use for differing Populus varietals will aid in matching specific varietals to site conditions and modeling how growth with be impacted by future climate conditions. We planted three eastern cottonwood (110412, ST66, S7C8) and three hybrid poplar (two P. deltoides x P. maximowicziii (6329, 8019) and one P. trichocarpa x P. deltoides (5077)) varietals at two sites with contrasting soils in north Mississippi. Sapflow rates were measured during the second growing season and tree biomass was measured at the end of the second growing season. We found that water use of varietals differed between sites with hybrid poplar 8019 exhibiting the highest water use at the sandy loam site and eastern cottonwood S7C8 using the most water at the clay loam site. Varietals were similar in whole tree WUE and, across both sites, biomass growth was positively correlated with whole tree WUE. Varietals also differed in their response to changes in soil moisture and stomatal sensitivity to vapor pressure deficit at each site. Overall, these results suggest that site conditions impact physiological functioning in terms of water use differently across varietals and that water use efficiency is important for biomass growth.