Highlights Forest responses to global climate change since the last ice age. In a recently accepted paper in the prestigious journal Ecology Letters, Holden scientist Juliana Medeiros and collaborators from the University of Kansas sought to answer the question: do plant species and families vary in physiological responses to global change? Studies such as this are critical for understanding the mechanisms that cause changes in plant species distributions across geologic time. The study investigated changes in photosynthetic physiology for a variety of trees and plants from a mixed conifer forest in the Snake Range Mountains of central Nevada, a community that underwent significant changes in community composition over the past 30,000 years. The results indicate that the photosynthetic physiology of most
plants was altered in response to changing conditions since the last ice age. However, plant families and species differed in the timing and magnitude of these responses. In fact, the responses were more similar within families than within co-occurring communities. This suggests that plant evolutionary history has been more important than plant physiology in determining plant community composition over recent geologic history. The paper is entitled Evolutionary history underlies plant physiological responses to global change since the Last Glacial Maximum, by Katie M. Becklin (University of Kansas), Juliana S. Medeiros (The Holden Arboretum), Kayla R. Sale (University of Kansas) and Joy K. Ward (University of Kansas).
Do low intensity fires reduce shrub encroachment in southern Ohio oak barrens? Land managers often use prescribed fires to maintain open structure and herb layer diversity in fire prone ecosystems, such as the oak barrens of southern Ohio. However, burning under conditions that generate low severity fires can actually facilitate woody plant encroachment, possibly because these fires stimulate shrub sprouting. In a paper recently accepted by the journal Restoration Ecology, Holden scientist Sheryl Petersen and Paul Drewa (Case Western Reserve University) report the results of a five-year study in southern Ohio oak barrens where small experimental burns were compared to clipping treatments (cutting above ground stems) to test if low severity fires better control unwanted woody plants as compared to clipping. The study found that both treatments killed shrub stems, but shrubs
rapidly grew new stems from underground organs. This caused a temporary reduction in shrub cover, but did not change stem densities. Further, the diversity and abundance of herbaceous species was not affected by treatments, but was affected by seasonal changes in precipitation. Thus, burning under marginal conditions may not reverse invasion of these oak barrens by unwanted woody plants. Land managers may need to avoid burning under some conditions and utilize other methods for shrub control. The paper is entitled Effects of biennial fire and clipping on woody and herbaceous ground layer vegetation: Implications for restoration and management of oak barren ecosystems, by Sheryl M. Petersen and Paul B. Drewa.
BRISTLECONE PINE SYSTEM OUT WEST
CHINQUAPIN OAK BARREN IN SOUTHERN OHIO WHERE PETERSEN AND DREWA STUDIED EFFECTS OF FIRE ON UNWANTED WOODY SHRUBS THAT CAN ALTER PLANT COMMUNITIES IN THESE FIRE PRONE FORESTS. THIS FOREST IS IN PIKE COUNTY OHIO AND IS OWNED AND MANAGED BY THE NATURE CONSERVANCY.
A photo identified as a Louisiana waterthrush in the spring 2014 issue of Leaves magazine is actually a northern waterthrush. We apologize for the error.
Summer 2014
Correction
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