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Effects of Simulated MPB on Hydrology and Post-attack Vegetation & Below-ground Dynamics

Principal investigators: Uldis Silins and Ellen Macdonald Ph.D. projects: Anne McIntosh and Pablo Pi単a Lead field technician: Pete Presant


Relative impact

?

Time


MPB - Unique disturbance agent • Larger & older trees selectively killed – but remain standing (vs logging) Æ needles can remain 3-5 yrs+

• Understory & soil layers not directly affected (vs logging or fire)

• Return of nonvolatile nutrients to the soil & response of vegetation production are slower (vs stand-replacing fire)

3


Broad research questions • How much extra water is produced after different levels of “red attack” ? (Pablo Piña) • What are the early trajectories of post-attack

vegetation and below-ground responses after different levels of “red attack” ? (Anne McIntosh)


Approach & treatments • Don’t wait for MPB (issue of “control”; B.C.) • Simulate MPB attack – variable density herbicide treatment • • • •

Control (untreated) Simulated MPB attack (50% overstory kill) Simulated MPB attack (100% overstory kill) Clearcut - harvested to simulate “salvage logging” management

5


2.2 ha

x1

1.2 ha

x2

z z

1 year pre-treatment measurements 2 years post-treatment measurements 2008

2009

12 stands 2010

2011

Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Au

- instrumentation

Pre-Treatment year

Post-Treatment Year 1

Post-Treatment Year 2


Study area & design • Pure pine ~ 120 yrs • Medium site index • 22-24 m height z z

Process studies Water balance - before-after: treatment-control Before

After

Treatment

Control

z

Understory vegetation - replicated (repeated measures)


2008

2009

2010

2011

Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Au

- instrumentation

Pre-Treatment year

Post-Treatment Year 1

Post-Treatment Year 2


• •

2008

Glyphosate – late June ’09 Harvest – July ‘09

2009

2010

2011

Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Au

- instrumentation

Pre-Treatment year

Post-Treatment Year 1

Post-Treatment Year 2


Canopy regulated environmental factors Air temperature

• Understory light, air temperature, humidity, wind, etc.

Vapor pressure deficit

• Understory microclimate (compared to canopy) Wind

• Air temperature (11 % lower, 1-2 oC) • Moisture demand (14 % lower) • Wind (51 % lower)


Canopy regulated environmental factors Air temperature

Pre-treatment Post-treatment

• Understory light, air temperature, humidity, wind, etc.

Vapor pressure deficit

• Change in understory microclimate (@3 m ht) Wind

• Air temperature - Tiny increase • Moisture demand – small/moderate increase • Wind – large increase • BATC – powerful approach to document changes


Post-attack hydrologic response Pablo Pina, PhD Student How much extra water is produced after different levels of “red attack� ? 1. Changes in overstory rainfall interception 2. Changes individual tree & stand level transpiration - Can surviving trees compensate (use more water) 3. Changes in forest floor and soil moisture storage 4. Changes in water table level, groundwater


Vertical water balance framework Gross precipitation + Evaporative demand

Canopy interception

Overstory transpiration

Forest floor interception Soil moisture storage


Rainfall interception Interception = Gross precipitation – (Stemflow+Throughfall)-(Throughfall-Forest floor flow)

Canopy interception

Canopy interception

Overstory transpiration

Forest floor interception

Soil moisture storage

Forest floor interception


Canopy interception

6m

Throughfall Stemflow

N= 4

N =3 Gross precipitation


Canopy storage capacity (S) = 8.1 mm Interception loss (mm)

12

Threshold

10 8 6 4 2 0 0

5

Interception loss

10

15

Predicted

20

25

Storm (mm)

30

35

40

45


Forest floor interception 0.5 m

Forest floor quadrat

0.5 m

Monitoring quadrats N =4


Gross Precipitation (mm) 100 kill

Julian Day

50 kill Clearcut

Harvested

10 25

8 20

6 15

4 10

2 5

0 0

Forest Floor Recharge (mm)

12

152 155 158 161 164 167 170 173 176 179 182 185 188 191 194 197 200 203 206 209 212 215 218 221 224 227 230 233 236 239 242 245 248 251

Forest Floor Weight (Kg)

Post-treatment forest floor seasonal weight trends Control 30


Water holding capacity (mm)

Forest floor water holding capacity Threshold

12 10

~8.5 mm 8 6 4 2 0 0

2

4

6

8

10

Storage opportunity (mm)

12

14


Storm frequency distribution based on rainfall intensity 80 70

70

Threshold Storm frequency

60 50 40 30 20 11 10 3

5 1

1

2

2

0 <3

3-6

6-9

9-12

12-15 15-18 18-21 21-24 24-27 27-30 30-33

(mm)

>36


Overstory transpiration Canopy interception

Overstory transpiration

N=7 Forest floor interception

Soil moisture storage


mm/day

Pre-treatment 4 3.5 3 2.5 2 1.5 1 0.5 0

6

mm/day

5 4 3 2 1 0

Post-treatment

Hourly transpiration

100% Kill

50% Kill

Control


Soil moisture storage

Spot measurements soil moisture (TDR)

Canopy interception

Overstory transpiration

Time continuous soil moisture (WCR)

Forest floor interception

Soil moisture storage


Soil moisture at the Control plot

Soil moisture storage (mm)

20 cm

40 cm

60 cm

100 90 80 70 60 50 40 2008

2009

2010

Spring melt recharge


Soil Moisture at 20 cm depth Control

100 Kill

Clearcut

50 Kill

0.4

30

0.35

25

0.3

20

0.25

15

0.2

10

0.15

5

0.1 2008

0 2009

Spring melt recharge

2010

Year

Forest Floor Recharge (mm)

Soil Volumetric Water Content

Forest Floor Recharge


What will happen when the MPB kills the trees? Precipitation Normals 120

Site Data

425 mm 75% of annual gross precipitation)

100

mm

80 60 40 20 0 Jan

Feb Mar

Apr May Jun

Jul

Aug Sep

Oct

Nov Dec


Conclusions:

Canopy interception

Overstory transpiration

During the growing season: Forest floor interception

• Canopy interception ≈ 49% of Precip

Soil moisture storage

• Forest floor interception could be as high as canopy interception • An average tree transpires 5.5 liters/day = > ≈0.7 liters/m2 day • Transpiration could be 41% of precipitation • Understory evaporation? • Soil moisture recharge is mainly driven by spring snowmelt


Post-attack vegetation & below-ground responses Anne McIntosh, PhD Student What are the early trajectories of post-attack vegetation and below-ground responses after different levels of â&#x20AC;&#x153;red attackâ&#x20AC;? ?


Understory Overstory

Belowground


Understory Overstory ? MPB Belowground


MPB as a disturbance agent • Larger & older trees selectively killed but remain

standing (vs logging) • Understory & soil layers not directly affected (vs logging or fire) • Return of nonvolatile nutrients to the soil & response of vegetation production are slower (vs stand-replacing fire) OUTSIDE HISTORICAL RANGE: HOW WILL STANDS IN AB RESPOND ?


Post-attack vegetation & below-ground response objectives What are the early trajectories of post-attack vegetation and below-ground responses after different levels of â&#x20AC;&#x153;red attackâ&#x20AC;? ? 1. Changes in overstory forest structure 2. Changes in understory plant community composition (shrubs, seedlings, plants (herbs, grasses, bryophytes) 3. Recruitment of downed woody debris (DWD) 4. Changes in below-ground processes (nutrient availability, microbial community, decomposition)


Objective 1: Overstory

Characterize the overstory forest structure (0.02 ha plots) • • • • • •

Species Live status Dbh Height Crown vigor Cover (hemispherical photos) Measured before (2008) & after (2010) treatment

33


Basal area 60 LIVE DEAD

Basal area (m2/ha)

50

40

30

20

10

0 100%kill

50%kill

Control

Treatment

* Post-treatment will be measured in 2010

Salvage


Trees per hectare 2500 LIVE DEAD

Trees per Hectare

2000

1500

1000

500

0 100%kill

50%kill

Control

Salvage

Treatment

* Post-treatment will be measured in 2010

35


Mean DBH 25

All Live Dead

Mean dbh (cm)

20

15

10

5

0 100%kill

50%kill

Control

Salvage

Treatment

* Post-treatment will be measured in 2010

36


Objective 2: Understory Quantify differences in the understory plant community composition • Seedlings/Saplings (pine) • Advanced regeneration? MINIMAL • Germination study (future regeneration potential) • Plants (shrubs, forbs, graminoids, bryophytes, lichens) • Richness • Abundance (% cover) by species • Basal area (large shrubs, e.g., alder)


Germination study (2010) What is the regeneration potential of these stands after MPB? Quadrats on 5 substrates sowed with seed: • LFH < 2.5 cm • LFH > 2.5 cm • Mineral soil • Moss • Dead wood (decay class 4-5) Monitor germination weekly


Understory richness

Mean Richness by Stand

35 30

2008 2009

25 20 15 10 5 0 100%kill

50%kill

Control

Treatment

Salvage

39


Understory cover 180 160

ALDER FERN BRYOPHYTE GRASS SHRUB HERB

140

Cover (%)

120 100 80 60 40 20 0 08

09

100Kill

08

09

50Kill

08

09

Control

Treatment by Year

08

09

Salvage


Understory cover: post-treatment (2009) 180

ALDER FERN BRYOPHYTE

160

GRASS SHRUB HERB

140

Cover (%)

120 100 80 60 40 20

a

a

a

b

100%kill

50%kill

Control

Salvage

0

Treatment


Objective 3: Downed woody debris

Quantify DWD â&#x20AC;˘ Transects: biomass estimates (Megagrams/ha)

42


Down Woody Debris (Megagrams/ha)

DWD biomass 60 2008 2009

50 40 30 20 10 0 100%kill

50%kill

Control

Treatment

Salvage


Objective 4: Below-Ground • Quantify differences in below-ground attributes • Decomposition (cellulose paper in mesh bags) • pH • Microbial biochemical activity & biomass • Community-level physiological profiles (CLPP) • Phospholipid fatty acid (PLFA) analysis • Nutrient availability (PRS probes) • Soil moisture (TDR)

44


Decomposition 100 2008 2009

Mass loss (%)

80

60

40

20

0 100%kill

50%kill

Control

Treatment

Salvage

45


pH 5 2008 2009

4

pH

3

2

1

0 100%kill

50%kill

Control

Treatment

Salvage

46


40 30

2008 2009

20 10

-

+

Total N (NO3 and NH4 ) Supply Rate 2 (micrograms/10cm /summer burial)

Total Nitrogen

0 100%kill

50%kill

Control

Salvage

Treatment

47


30 25

2008 2009

20

2

(micrograms/10cm /summer burial)

-

N (NO3 ) Supply Rate

NO3-

15 10 5 0 100%kill

50%kill

Control

Treatment

Salvage

48


10 2008 2009

2

(micrograms/10cm /summer burial)

+

N (NH4 ) Supply Rate

NH4+

5

0 100%kill

50%kill

Control

Salvage

Treatment

49


Understory Overstory â&#x20AC;ŚMPB (short-term)

Belowground


Recap & the futureâ&#x20AC;Ś


Project timeline … Fall 2007 – May 2008: site selection, plot layout, instrumentation June 2008 – 2009: pre-treatment data collection June 2009 – July 2009: treatment application June 2009 – 2010: 1st post-treatment year data collection June 2010 – 2011: 2nd post-treatment year data collection June 2011 – Mar 2012: analysis and write-up Subsequent data collection?


What information will we have? Characterize water balance of these forests: • Where the water is/goes • How much water do they use? Characterize forest structure, vegetation, below-ground • Relationships: canopy, understory vegetation, soils • Potential for tree regeneration What happens when the trees die and stay standing?


Short-term responses of lodgepole pine forests to this unique disturbance Transpiration Interception

Future forest development

Soil water Soil nutrients

Below-ground communities Below-ground processes Light?

Understory cover Species-specific responses

Understory community change Recover water balance?


Short-term responses of lodgepole pine forests to this unique disturbance Effects of gradient of disturbance: Water yield? Vegetation change? Recovery of water balance? Tree regeneration? Future forest development? LONGER TERM RESPONSESâ&#x20AC;Ś.?


Support for the work • • • • • • •

Foothills Research Institute FRIAA / AB SRD West Fraser Timber Co. Ltd. NSERC CONACYT Milo Mihajlovich Field Assistants

…Thank you for listening For further information: uldis.silins “at” ales.ualberta.ca ellen.macdonald “at” ales.ualberta.ca ppina “at” ualberta.ca amcintos “at” ualberta.ca


Mpbep 2010 03 prsnttn effectsofsimulatedmpbonhydrologyandpostattackvegetationandbelowgrounddynamicss  

http://foothillsri.ca/sites/default/files/null/MPBEP_2010_03_Prsnttn_EffectsofSimulatedMPBonHydrologyandPostAttackVegetationandBelowGroundDy...

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