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- Severity rating systems are fundamental to understanding the impacts of disturbance agents in forest stands. The balsam woolly adelgid (BWA), Adelges piceae (Ratzeburg) (Hemiptera: Adelgidae), is an invasive forest pest in North America that infests and causes mortality in true fir, Abies spp. There is currently no single system for evaluating damage caused by BWA in the western United States. Because range expansion through favored habitat is inevitable, it is imperative to begin long-term monitoring using a unified approach to evaluate changing conditions and hasten management opportuniti...AuthorsKathryn H. Hrinkevich, Robert Progar, David C. ShawSourceForest Science. 62(2): 181-189.Year2016
- Estimates of species’ vital rates and an understanding of the factors affecting those parameters over time and space can provide crucial information for management and conservation. We used mark–recapture, reproductive output, and territory occupancy data collected during 1985–2013 to evaluate population processes of Northern Spotted Owls (Strix occidentalis caurina) in 11 study areas in Washington, Oregon, and northern California, USA. We estimated apparent survival, fecundity, recruitment, rate of population change, and local extinction and colonization rates, and investigated relationshi...AuthorsKatie M. Dugger, Eric D. Forsman, Alan B. Franklin, Raymond J. Davis, Gary C. White, Carl J. Schwarz, Kenneth P. Burnham, James D. Nichols, James E. Hines, Charles B. Yackulic, Paul F. Doherty, Larissa Bailey, Darren A. Clark, Steven H. Ackers, Lawrence S. Andrews, Benjamin Augustine, Brian Biswell, Jennifer Blakesley, Peter C. Carlson, Matthew J. Clement, Lowell V. Diller, Elizabeth M. Glenn, Adam Green, Scott A. Gremel, Dale R. Herter, J. Mark Higley, Jeremy Hobson, Rob B. Horn, Kathryn P. Huyvaert, Christopher McCafferty, Trent McDonald, Kevin McDonnell, Gail S. Olson, Janice A. Reid, Jeremy Rockweit, Viviana Ruiz, Jessica Saenz, Stan SovernKeywordsSourceThe Condor. 118(1): 57-116.Year2016
- Hot water extraction (HWE) partially removes hemicelluloses from wood while leaving the majority of the lignin and cellulose; however, the lignin partially migrates to the inner surfaces of the cell wall where it can be deposited as a layer that is sometimes visible as droplets. This lignin-rich material was isolated via Soxhlet extraction with dichloromethane to investigate its rheological behavior in blends with high-density polyethylene (HDPE), a common material in wood plastic composites (WPCs). Pyrolysis gas-chromatography/mass spectrometry (Py-GC/MS) and electrospray ion mass...AuthorsManuel R. Pelaez-Samaniego, Vikram Yadama, Manuel Garcia-Perez, Eini C. Lowell, Rui Zhu, Karl EnglundKeywordsSourceHolzforschung. 70(1): 31-38.Year2016
- Recent vulnerability assessments, conducted in diverse regions in the northwestern United States, indicate that many commonalities exist with respect to projected vulnerabilities to climate change. Dry forests are projected to have significant changes in distribution and abundance of species, partially in response to higher temperature and lower soil moisture, but mostly in response to projected increases in extreme events and disturbances—drought, wildfire, and insect outbreaks. Wildfire and mountain pine beetles have caused extensive mortality across millions of hectares in this region...AuthorsJessica Halofsky, David L. PetersonSourceAtmosphere. 7(3): 46-.Year2016
- Tephra fall influences the structure and dynamics of Andean Nothofagus (beech) forests in Puyehue National Park, Chile. Forest mortality and subsequent establishment, structure and composition have been affected by the eruption of the Puyehue-Cordon Caulle volcano complex.AuthorsMauricio Montiel, Mauro E González, Charlie CrisafulliKeywordsSourceAnales del Instituto de la Patagonia. 44(3): 5-11.Year2016
- The concept of iso- vs. anisohydry has been used to describe the stringency of stomatal regulation of plant water potential (ψ). However, metrics that accurately and consistently quantify species’ operating ranges along a continuum of iso- to anisohydry have been elusive. Additionally, most approaches to quantifying iso/anisohydry require labour-intensive measurements during prolonged drought. We evaluated new and previously developed metrics of stringency of stomatal regulation of ψ during soil drying in eight woody species and determined whether easily-determined leaf pressure–volume...AuthorsFrederick Meinzer, David R. Woodruff, Danielle E. Marias, Duncan D. Smith, Katherine A. McCulloh, Ava R. Howard, Alicia L. Magedman, Josep PenuelasKeywordsSourceEcology Letters. 19(11): 1343-1352.Year2016
- Occupancy modeling is a widely used analytical technique for assessing species distributions and range dynamics. However, occupancy analyses frequently ignore variation in abundance of occupied sites, even though site abundances affect many of the parameters being estimated (e.g., extinction, colonization, detection probability). We introduce a new model (“dynamic N-occupancy”) capable of providing accurate estimates of local abundance, population gains (reproduction/immigration), and apparent survival probabilities while accounting for imperfect detection using only detection/nondetection...AuthorsSam Rossman, Charles B. Yackulic, Sarah P. Saunders, Janice A. Reid, Ray Davis, Elise F. ZipkinKeywordsSourceEcology. 97(12): 3300-3307.Year2016
- Although climate warming is generally expected to facilitate upward advance of forests, conifer seedling regeneration and survival may be hindered by low substrate moisture, high radiation, and both low and high snow accumulation. To better understand substrate-related factors promoting regeneration in the alpine treeline ecotone, this study compared 2 substrates supporting conifer seedlings: rotten downed wood and adjacent soil. Study locations, each with 3 levels of incoming radiation, were randomly selected at forest line–alpine meadow borders in Pacific Northwest wilderness areas...AuthorsAdelaide C. Johnson, J. Alan YeakleyKeywordsSourceMountain Research and Development. 36(4): 443-451.Year2016
- La historia de las truchas del Pacífico, pertenecientes al género Oncorhynchus, es una historia muy interesante que se basa en la persistencia y diversificación de sus especies debido, en gran parte, al dinamismo propio que existe en su medio ambiente. Desde el oeste de Norteamérica, extendiéndose hasta el este de Asia, las truchas del Pacífico han experimentado la influencia de los avances y retrocesos de glaciares, vulcanismo, condiciones extremas en el caudal de los ríos, al igual que eventos geotectónicos, que han permitido la formación de cordilleras y mesetas. Dichos eventos son los...AuthorsBrooke PenalunaKeywordsSourceIn: Ruiz-Luna A.; Garcia de Leon F. J. eds. La Trucha Dorada Mexicana. Mexico. 183-188. Chapter 14.Year2016
- Increasing aridity as a result of climate change is expected to exacerbate tree mortality. Reducing forest basal area – the cross-sectional area of tree stems within a given ground area – can decrease tree competition, which may reduce drought-induced tree mortality. However, neither the magnitude of expected mortality increases, nor the potential effectiveness of basal area reduction, has been quantified in dryland forests such as those of the drought-prone Southwest US. We used thousands of repeatedly measured forest plots to show that unusually warm and dry conditions are related to...AuthorsJohn B Bradford, David M. BellSourceFrontiers in Ecology and the Environment. 15(1): 11-17.Year2016