Treesearch
Displaying 16,541 - 16,550 of 64,721 Publications- Bottomland sediments from the southern Blue Ridge Mountains provide a coarse-resolution, multi-millennial stratigraphic record of past regional forest disturbance (soil erosion). This record is represented by 12 separate vertical accretion stratigraphic profi les that have been dated by radiocarbon, luminescence, cesium-137, and correlation methods continuously spanning the past 3,000 years of pre-settlement (pre-dating widespread European American settlement) and postsettlement strata. Post-settlement vertical accretion began in the late 1800s, appears to be about an order of magnitude...AuthorsDavid S. LeighKeywordsSourceIn: Greenberg, CH and BS Collins (eds.). Natural disturbances and historic range of variation: Type, frequency, severity, and post-disturbance structure in central hardwood forests USA. Managing Forest Ecosystems. Springer.Year2016
- We merge concepts from stomatal optimization theory and cohesion–tension theory to examine the dynamics of three mechanisms that are potentially limiting to leaf-level gas exchange in trees during drought: (1) a ‘demand limitation’ driven by an assumption of optimal stomatal functioning; (2) ‘hydraulic limitation’ of water movement from the roots to the leaves; and (3) ‘non-stomatal’ limitations imposed by declining leaf water status within the leaf. Model results suggest that species-specific ‘economics’ of stomatal behaviour may play an important role in differentiating species along the...AuthorsKimberly Novick, Chelcy F. Miniat, James VoseKeywordsSourcePlant, Cell & EnvironmentYear2016
- We studied seed germination and early seedling growth of Pinus densata to explore the range of variability within the species and to inform afforestation practices. Phenotypes were evaluated at a forest tree nursery under conditions that support Pinus yunnanensis, one of the presumed parental species of P. densata. Seeds were collected from 20 open-pollinated trees within each of eight autochthonous populations representing the natural distribution of P. densata in China to assess variation in germination traits and early seedling growth, and to examine the relationships among these...AuthorsYulan Xu, Nianhui Cai, Bin He, Ruili Zhang, Wei Zhao, Jianfeng Mao, Anan Duan, Yue Li, Keith WoesteKeywordsSourceJournal of Forestry Research. 27(2): 283-294.Year2016
- Sagebrush ecosystems are among the largest and most threatened ecosystems in North America. Greater sage-grouse has served as the bellwether for species conservation in these ecosystems and has been considered for listing under the Endangered Species Act eight times. In September 2015, the decision was made not to list greater sage-grouse, but to reevaluate its status in 5 years. Concerns over sage-grouse and associated habitats have set in motion sweeping Federal and State land management plan changes and proactive science-based conservation actions to address threats within the realm of...AuthorsDeborah M. Finch, D. A. Boyce, Jeanne C. Chambers, C. J. Colt, Kas Dumroese, Stanley G. Kitchen, C. McCarthy, Susan E. Meyer, Bryce A. Richardson, Mary M. Rowland, Mark A. Rumble, Michael K. Schwartz, Monica Tomosy, Michael WisdomKeywordsSourceGen. Tech. Rep. RMRS-GTR-348. Fort Collins, CO; U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, 54 p.Year2016
- Traditionally, lumber cutting systems in rough mills have either first ripped lumber into wide strips and then crosscut the resulting strips into component lengths (rip-first), or first crosscut the lumber into component lengths, then ripped the segments to the required widths (crosscut-first). Each method has its advantages and disadvantages. Crosscut-first typically works best for the production of wider components, while rip-first favors the production of narrower and longer components. Thus, whichever type of processing method is selected for a given rough mill usually depends on the...AuthorsEd Thomas, Urs BuehlmannSourceBioResources 11(1): 1477-1493.Year2016
- Vegetation, forest floor, and soils were resampled at a mixed oak site in eastern Tennessee that had been subjected to stem only (SOH), whole-tree harvest (WTH), and no harvest (REF) 33 years previously. Although differences between harvest treatments were not statistically significant (P < 0.05), average diameter, height, basal area and biomass were 8–18% lower in the WTH than in the SOH treatment 33 years after harvest whereas they differed by 2% 15 years after harvest. In contrast to results 15 years post-harvest, total forest floor mass and nutrient contents were twofold greater in the...AuthorsD.W. Johnson, C.C. Trettin, D.E. ToddSourceForest Ecology and ManagementYear2016
- Many environmental challenges are exacerbated within the urban landscape, such as stormwater runoff and flood risk, chemical and particulate pollution of urban air, soil and water, the urban heat island, and summer heat waves. Urban trees, and the urban forest as a whole, can be managed to have an impact on the urban water, heat, carbon and pollution cycles. However, there is an increasing need for empirical evidence as to the magnitude of the impacts, both beneficial and adverse, that urban trees can provide and the role that climatic region and built landscape circumstance play in...AuthorsS. J. Livesley, E. Gregory McPherson, C. CalfapietraSourceJournal of Environmental Quality. 45: 119-124Year2016
- Urban forestry is an important green infrastructure strategy because healthy trees can intercept rainfall, reducing stormwater runoff and pollutant loading. Surface saturation storage capacity, defined as the thin film of water that must wet tree surfaces before flow begins, is the most important variable influencing rainfall interception processes. Surface storage capacity is known to vary widely among tree species, but it is little studied. This research measured surface storage capacities of 20 urban tree species in a rainfall simulator. The measurement system included a rainfall...AuthorsQingfu Xiao, E. Gregory McPhersonSourceJournal of Environmental Quality. 45: 188-198Year2016
- Non-structural carbohydrates (NSC) in plant tissue are frequently quantified to make inferences about plant responses to environmental conditions. Laboratories publishing estimates of NSC of woody plants use many different methods to evaluate NSC. We asked whether NSC estimates in the recent literature could be quantitatively compared among studies. We also asked whether any differences among laboratories were related to the extraction and quantification methods used to determine starch and sugar concentrations. These questions were addressed by sending sub-samples collected from five...AuthorsMarc Bonhomme, Audrey G. Quentin, Elizabeth A. Pinkard, Michael G. Ryan, David T. Tissue, L. Scott Baggett, Henry D. Adams, Pascale Maillard, Jacqueline Marchand, Simon M. Landhausser, Andre Lacointe, Yves Gibon, William R. L. Anderegg, Shinichi Asao, Owen K. Atkin, Renee A. Smith, Frank Sterck, Joseph R. Stinziano, Caroline Claye, Pak S. Chow, Anne Clement-Vidal, Noel W. Davies, L. Turin Dickman, Rita Dumbur, David S. Ellsworth, Kristen Falk, Lucía Galiano, Jose M. Grunzweig, Henrik Hartmann, Gunter Hoch, Sharon M. Hood, Joanna E. Jones, Takayoshi Koike, Iris Kuhlmann, Francisco Lloret, Melchor Maestro, Shawn D. Mansfield, Jordi Martinez-Vilalta, Mickael Maucourt, Nathan G. McDowell, Annick Moing, Bertrand Muller, Sergio G. Nebauer, Ulo Niinemets, Sara Palacio, Frida Piper, Eran Raveh, Andreas Richter, Gaelle Rolland, Teresa Rosas, Brigitte Saint Joanis, Anna Sala, Faride Unda, Makoto Watanabe, Danielle A. Way, Lasantha K. Weerasinghe, Birgit Wild, Erin Wiley, David R. Woodruff, Mari TobiasKeywordsSourceTree Physiology. 35: 1146-1165.Year2016
- Natural resource vulnerability to climate change can depend on the climatology and ecological conditions at a particular site. Here we present a conceptual framework for incorporating spatial variability in natural resource vulnerability to climate change in a regional-scale assessment. The framework was implemented in the first regional-scale vulnerability assessment conducted by the US Forest Service. During this assessment, five subregional workshops were held to capture variability in vulnerability and to develop adaptation tactics. At each workshop, participants answered a questionnair...AuthorsPolly C. Buotte, David L. Peterson, Kevin S. McKelvey, Jeffrey A. HickeSourceJournal of Environmental Management. 169: 313-318.Year2016