Treesearch
Displaying 18,541 - 18,550 of 64,781 Publications- U.S. hardwood sawmill log procurement practices are evolving because of the recent economic recession, market and supply chain shifts, and changing landowner objectives, among other factors. The objective of this study was to characterize the log procurement practices of hardwood sawmills and to characterize the role that log brokers play in supplying the sawmill industry with raw material. To meet this objective, a mail survey on hardwood log procurement practices in the U.S. hardwood sawmill industry was conducted. Survey respondents highlighted several factors that had major effects on...AuthorsAdrienn Andersch, Iris B. Montague, Urs Buehlmann, Jan K. WiedenbeckSourceBioResources. (10)1: 1224-1244.Year2015
- Dead trees play an important role in forests, with snags and coarse woody debris (CWD) used by many bird and mammal species for nesting, resting, or foraging. However, too much dead wood can also contribute to extreme fire behavior. This tension between dead wood as habitat and dead wood as fuel has raised questions about appropriate quantities in fire-dependent forested ecosystems. Three plots installed in mixed conifer forest of the central Sierra Nevada in 1929 illustrate how amounts and sizes of dead wood have changed through time as a result of logging and fire exclusion. Diameter of...AuthorsEric E. KnappKeywordsSourceForest Ecology and Management. 339: 87-95Year2015
- The RNA interference (RNAi) technology has been widely used in insect functional genomics research and provides an alternative approach for insect pest management. To understand whether the emerald ash borer (Agrilus planipennis), an invasive and destructive coleopteran insect pest of ash tree (Fraxinus spp.), possesses a strong RNAi machinery that is capable of degrading target mRNA as a response to exogenous double-stranded RNA (dsRNA) induction, we identified three RNAi pathway core component genes, Dicer-2, Argonaute-2 and R2D2, from the A. planipennis genome sequence. Characterization...AuthorsChaoyang Zhao, Miguel A. Alvarez Gonzales, Therese M. M. Poland, Omprakash MittapalliKeywordsSourceJournal of Insect Physiology. 72: 70-78.Year2015
- Development of commercial Eucalyptus plantations has been limited in the United States because of the species’ sensitivity to freezing temperatures. Recently developed genetically engineered clones of a Eucalyptus hybrid, which confer freeze tolerance, could expand the range of commercial plantations. This study explores how freeze-tolerant Eucalyptus might be adopted as a preferred land use based on comparative returns and a real options land-use switching model. Climate factors other than freezing are assumed to limit potential adoption to the southeastern region of the United States....AuthorsDavid N. Wear, Ernest Dixon IV, Robert C. Abt, Navinder SinghSourceForest ScienceYear2015
- Rates of biodiversity loss are higher in freshwater ecosystems than in most terrestrial or marine ecosystems, making freshwater conservation a priority. However, prioritization methods are impeded by insufficient knowledge on the distribution and conservation status of freshwater taxa, particularly invertebrates. We evaluated the extinction risk of the world’s 590 freshwater crayfish species using the IUCN Categories and Criteria and found 32% of all species are threatened with extinction. The level of extinction risk differed between families, with proportionally more threatened species...AuthorsNadia I. Richman, Monika Böhm, Susan B. Adams, Fernando Alvarez, Elizabeth A. Bergey, John J. S. Bunn, Quinton Burnham, Jay Cordeiro, Jason Coughran, Keith A. Crandall, Kathryn L. Dawkins, Robert J. DiStefano, Niall E. Doran, Lennart Edsman, Arnold G. Eversole, Leopold Füreder, James M. Furse, Francesca Gherardi, Premek Hamr, David M. Holdich, Pierre Horwitz, Kerrylyn Johnston, Clive M. Jones, Julia P. G. Jones, Robert L. Jones, Thomas G. Jones, Tadashi Kawai, Susan Lawler, Marilu López-Mejía, Rebecca M. Miller, Carlos Pedraza-Lara, Julian D. Reynolds, Alastair M. M. Richardson, Mark B. Schultz, Guenter A. Schuster, Peter J. Sibley, Catherine Souty-Grosset, Christopher A. Taylor, Roger F. Thoma, Jerry Walls, Todd S. Walsh, Ben CohenSourcePhilosophical Transactions of the Royal Society B: Biological Sciences. 370: 20140060Year2015
- Multi-trophic interactions between pine bark beetles, their host trees, and predators are mediated in part by volatile terpenes in host tree oleoresin that can influence aggregation and/or host finding by both prey and predator species. The southern pine beetle, Dendroctonus frontalis Zimmermann, mass-attacks pine trees in response to its aggregation pheromone combined with host resin odors including a-pinene. We investigated discrimination of apinene enantiomers in olfactory responses of D. frontalis, and in behavioral responses of D. frontalis and its major clerid predator, Thanasimus...AuthorsJenny C. Staeben, Brian Sullivan, John T. Nowak, Kamal J.K. GandhiKeywordsSourceChemoecology, published online 25 Oct 2014Year2015
Field assessment of hybridization between Laricobius nigrinus and L. rubidus, predators of Adelgidae
Two adelgid predators, Laricobius nigrinus Fender and Laricobius rubidus LeConte, were recently discovered to produce hybrid progeny in the eastern United States. L. rubidus is native to eastern North America where it feeds on pine bark adelgid (Pineus strobi Hartig) and L. nigrinus is native to western North America and was introduced to the eastern United States in 2003 for biological control of hemlock woolly adelgid (Adelges tsugae Annand). Currently, L. nigrinus and L. rubidus form a mosaic of hybrid zones throughout the eastern United States. It is not known whether these zones will...AuthorsMelissa J. Fischer, Nathan P. P. Havill, Carlyle C. Brewster, Gina A. Davis, Scott M. Salom, Loke T. KokKeywordsSourceBiological Control. 82: 1-6.Year2015- Bohemian knotweed spreads aggressively along rivers. This invasive weed chokes waterways, displaces native plants, erodes riverbanks, and keeps tree seedlings from growing. Communities in the Pacific Northwest spend millions of dollars to eradicate it on the assumption that it harms fish habitats. But knotweed is difficult to kill. It takes years of herbicide applications to destroy the weed, and a single fragment can sprout and start new infestations. Also, control programs typically don’t evaluate whether native plants reestablish themselves after knotweed is cleared. Forest Service...AuthorsNatasha Vizcarra, Shannon ClaesonSourceScience Findings 169. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 6 p.Year2015
- The emerald ash borer (EAB; Agrilus planipennis) is an introduced Asian beetle species that was first detected in trees in the Fraxinus (ash) genus in the United States in 2002. Female EAB beetles lay between 40 to 70 eggs in cracks, crevices, and beneath bark flakes. The eggs hatch within about 2 weeks, larvae bore through the outer bark, and begin eating the inner cambium of the wood. As larvae carve galleries through the cambium, they effectively disrupt the ability of the tree to transport water and nutrients. The larvae eventually girdle the tree, resulting in canopy decline and death...AuthorsSonja OswaltSourcee-Science Update SRS-108. U.S. Department of Agriculture Forest Service, Southern Research Station. 5 p.Year2015
- Development of efficient forest wildfire policies requires an understanding of the underlying reasons behind forest fire occurrences. Globally, there is a close relationship between forest wildfires and human activities; most wildfires are human events due to negligence (e.g., agricultural burning escapes) and deliberate actions (e.g., vandalism, pyromania, revenge, land use change attempts). We model the risk of wildfire as a function of the spatial pattern of urban development and the abandonment/intensity of agricultural and forestry activities, while controlling for biophysical and...AuthorsM. L. Chas-Amil, Jeffrey P. Prestemon, C. J. McClean, J. TouzaKeywordsSourceApplied Geography 56 (2015) 164-176Year2015