Treesearch

Hemlock woolly adelgid (Adelges tsugae Annand) (HWA) is an invasive forest insect sweeping across the native range of eastern (Tsuga canadensis [L.] Carr.) and Carolina (Tsuga caroliniana Engelm.) hemlocks, threatening to severely reduce eastern hemlock extent and to push Carolina hemlock to extirpation. HWA poses a significant threat to these eastern US natives, now infesting hemlocks across 19 states and more than 400 counties. For the long-term preservation of the species, ex situ genetic resource conservation efforts such as seed collection, storage, and adelgid-resistant hemlock...

The mechanisms governing the ability of water-soluble polymers (WSP) to alter the rheological properties of lignocellulosic biomass to achieve processing advantages are investigated. Lignocellulosic fiber surface chemistry is found to be an important factor in the efficacy of WSPs as rheological modifiers, and a strong correlation between the amount of adsorbed polymer at fiber surfaces and the yield stress of the fiber suspension indicate that adsorption of polymer is important for rheological modification. Three fiber suspensions of varying physical chemistry were produced from Aspen...

Hydraulic geometry offers robust scaling of channels across many orders of magnitude in natural rivers, irrigation canals, and laboratory channels (Ferguson 1986). Although the authors’ analysis focuses on fluvial deposits, it is worth noting that hydraulic geometry relations can be developed for a variety of fluids, which may have relevance for some Martian channels given that differences in gravity and atmospheric conditions (pressure, temperature, and, thus, viscosity) may cause channel hydraulics and flow rheology (Froude and Reynolds numbers) to differ from those on Earth. Data from...

Utah lotus (Lotus utahensis Ottley) is a North American leguminous forb that may hold promise for rangeland revegetation in the western United States for diversifying planting mixtures, attracting pollinators, providing high-quality forage, and expanding habitats for insects needed by sage-grouse chicks. Fourteen wildland seed collections of Utah lotus originating from Nevada and Utah were assessed for genetic variation of a wide range of phenotypic traits and genetic relationships. Population structure estimates defined by 552 amplified fragment length polymorphism (AFLP) markers identifie...

Human‐caused climate change is predicted to affect the frequency of hazard linked extremes. Unusually large wildfires, individually or expressed as area burned over time, are a type of extreme event that is constrained by climate and can be a hazard to society but also an important ecological disturbance. Here we project changes in the frequency of extreme monthly area burned by wildfires for the end of the 21st century for a wildfire‐prone region in the southeast United States. Predicting changes in area burned is complicated by the large and varied uncertainties in how the climate will...

Wildfires, harvesting, and beetle outbreaks all have different effects on forest dynamics and biogeochemical responses. Responses to beetle outbreaks vary with forest species composition, understory conditions, tree size and age, and other factors. Larger trees are more susceptible to mountain pine beetle attack. Mixed-age stands at the Fraser Experimental Forest had lower overall tree mortality and greater recovery potential. These findings provide support for maintaining age, species, and structural diversity within headwater forests.

Forest management that creates a diversity of prey habitats in ponderosa pine and mixed-conifer forests is beneficial to gos-hawks. The desired habitat diversity includes all tree age classes with a focus on older trees in fine-scale mosaics composed of groups of trees, scattered individual trees, large snags and logs and small openings with species-diverse and productive herbaceous-shrub communities.

Forests in the eastern United States have become fragmented by urban development and agriculture, creating a landscape of remnant forest patches. Many bird species rely on these fragments for breeding habitat, but habitat selection in these patches is not well-understood. Our objective was to examine the effects of forest structure, native plants, and invertebrate biomass on the occupancy of an assemblage of common Eastern songbird species in suburban forest fragments. We collected data at 98 plots in remnant forest patches in Delaware and Maryland. Avian point counts were conducted three...

Background: Restriction site associated DNA sequencing (RADseq) has the potential to be a broadly applicable, low-cost approach for high-quality genetic linkage mapping in forest trees lacking a reference genome. The statistical inference of linear order must be as accurate as possible for the correct ordering of sequence scaffolds and contigs to chromosomal locations. Accurate maps also facilitate the discovery of chromosome segments containing allelic variants conferring resistance to the biotic and abiotic stresses that threaten forest trees worldwide. We used ddRADseq for genetic...