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Shawn Fraver

Concern over global environmental change and associated uncertainty has given rise to greater emphasis on fostering resilience through forest management. We examined the impact of standard silvicultural systems (including clearcutting, shelterwood, and selection) compared with unharvested controls on tree functional identity and functional diversity in three forest types distributed across the northeastern United States. Sites included the Argonne, Bartlett, and Penobscot Experimental Forests located in Wisconsin, New Hampshire, and Maine, respectively. We quantified functional trait means for leaf mass per area, specific gravity, maximum height, height achieved at 20 years, seed mass, drought tolerance, shade tolerance,...
Abstract (from Journal of Applied Ecology): Increasing heat and aridity in coming decades is expected to negatively impact tree growth and threaten forest sustainability in dry areas. Maintaining low stand density has the potential to mitigate the negative effects of increasingly severe droughts by minimizing competitive intensity. However, the direct impact of stand density on the growing environment (i.e. soil moisture), and the specific drought metrics that best quantify that environment, are not well explored for any forest ecosystem. We examined the relationship of varying stand density (i.e. basal area) on soil moisture and stand‐level growth in a long‐term (multi‐decadal), ponderosa pine Pinus ponderosa,...
Categories: Publication; Types: Citation
Deadwood moisture plays a major role in regulating deadwood decomposition rates and may also affect forest microclimate. Despite this, the temporal variability of deadwood moisture at 15-min time scales remains relatively unknown because techniques for using high-frequency sensors for tracking moisture at appropriate spatial and temporal intensities have been lacking. We installed a high-density sensor array in and around a downed log to gain a detailed assessment regarding the temporal variation of volumetric water content at multiple locations within one downed dead log, the source snag, and the surrounding soil. We also measured micrometeorological variables near the log in order to predict variability of the...
Categories: Publication; Types: Citation
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Overview This project examines the ecological impacts of several introduced and expanding forest insects and diseases on forest habitats across the northeastern US and upper Lake States region. To address these novel threats, this work applies large-scale, co-developed experimental studies documenting impacts of ash mortality from emerald ash borer on lowland black ash communities in the Lake States and northern hardwood forests in New England; regional assessments of the impacts of the climate change-mediated expansion of southern pine beetle into northeastern pine barren communities; and ecological characterizations of areas experiencing suppression efforts to reduce the spread of the introduced Asian long-horned...
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