Treesearch

In the southeastern United States, drought can pose a significant threat to forests by reducing the amount of available water, thereby stressing trees. Destructive changes in crown conditions provide the first visible indication of a problem in a forested area, making it a useful indicator for problems within an ecosystem. Forest Health and Monitoring (FHM) and Palmer’s Drought Severity Index (PDSI) data from 11 states in the southeastern United States were obtained in an effort to determine the role that drought, forest type, and ecoregion have in indicating differences in crown dieback....

Accuracy assessments of remote sensing products are necessary for identifying map strengths and weaknesses in scientific and management applications. However, not all accuracy assessments are created equal. Motivated by a recent study published in Forest Ecology and Management (Volume 342, pages 8–20), we explored the potential limitations of accuracy assessments related to characteristics of the field data: sampling bias and spatial resolution. The authors of the previous paper used data from variable radius plots near northern spotted owl nest sites to assess the predictive accuracy of...

Contributing to the worldwide biodiversity crisis are emerging infectious diseases, which can lead to extirpations and extinctions of hosts. For example, the infectious fungal pathogen Batrachochytrium dendrobatidis (Bd) is associated with worldwide amphibian population declines and extinctions. Sensitivity to Bd varies with species, season, and life stage. However, there is little information on whether sensitivity to Bd differs among populations, which is essential for understanding Bd-infection dynamics and for formulating conservation strategies.We experimentally investigated intraspeci...

Copper is currently used as the key component in wood preservatives despite the known tolerance of many brown-rot Basidiomycetes. Copper-tolerant fungi, like Fibroporia radiculosa, produce and accumulate high levels of oxalate when exposed to copper. To gain insight into the mechanism of oxalate production, four F. radiculosa isolates decaying untreated and 1.2% ammoniacal copper citrate-treated wood were evaluated for the differential expression of citrate synthase, isocitrate lyase, glyoxylate dehydrogenase, a succinate/fumarate antiporter, and a copper resistance-associated ATPase pump....

Communicating the scientific knowledge generated by the Pacific Northwest Research Station is integral to our mission. The 2014 Science Accomplishments reports highlights the breadth of the station’s research, the relevance of our science findings, and the application of these findings. The photographs throughout the report showcase the region where we work and how science is done.

The scientific and policy literature on climate change increasingly recognizes the vulnerabilities of indigenous communities and their capacities for resilience. The role of gender in defining how indigenous peoples experience climate change in the United States is a research area that deserves more attention. Advancing climate change threatens the continuance of many indigenous cultural systems that are based on reciprocal relationships with local plants, animals, and ecosystems. These reciprocal relationships, and the responsibilities associated with them, are gendered in many indigenous...

We investigated potential source areas of dissolved organic carbon (DOC) in headwater streams by examining DOC concentrations in lysimeter, shallow well, and stream water samples from a reference catchment at the Hubbard Brook Experimental Forest. These observations were then compared to high-frequency temporal variations in fluorescent dissolved organic matter (FDOM) at the catchment outlet and the predicted spatial extent of shallow groundwater in soils throughout the catchment. While near-stream soils are generally considered a DOC source in forested catchments, DOC concentrations in...

Recent patterns of prolonged regional drought in southern boreal forests of the Great Lakes region, USA, suggest that the ecological effects of disturbance by wildfire may become increasingly severe. Losses of forest soil organic matter (SOM) during fire can limit soil nutrient availability and forest regeneration. These processes are also influenced by the composition of postfire SOM. We sampled the forest floor layer (i.e., full organic horizon) and 0-10cm mineral soil fromstands dominated by coniferous (Pinus banksiana Lamb.) or deciduous (Populus tremuloides Michx.) species 1-2months...

Oak decline is a widely distributed disease that results from an interacting set of factors in the Central Hardwood Region. Episodes of decline have been reported since before the turn of the twentieth century and from every state in the region. It is a stress-mediated disease that results from the interactions of physiologically mature trees, abiotic and biotic stressors that alter carbohydrate physiology, and opportunistic fungal pathogens and inner bark-feeding insects. Symptoms include reduced radial growth and slow, progressive crown dieback. Decline occurs over several years or...

There’s a tendency to think of the hardwood forests of the South as pristine, undisturbed, and unchanging places that provide habitat for diverse animal and plant species. Indeed, having large blocks of mature forest is important for many wildlife species. The leafy tree canopy, tall trunks, hard mast, dead trees with holes, cool and shady micro-environment, and thick leaf litter provide places to nest, forage, and hide for birds, salamanders, and other animals.