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Displaying 11,901 - 11,910 of 64,672 Publications- An extreme disturbance event is one in which any of its component disturbance forces and their interactions with affected systems have dimensions and responses that exceed the known range of variation expected of those parameters. If the exposed system does not respond or exhibits a low level response to an event, the event was not extreme to the exposed system, regardless of the dimensions of its disturbance forces. Extreme disturbance events are complex and require disaggregation to improve understanding of their effects. The areas affected by extreme events and the duration of the...AuthorsAriel LugoKeywordsSourceBiogeochemistryYear2018
- There are few whole-canopy or ecosystem scale assessments of the interplay between canopy temperature and photosynthesis across both spatial and temporal scales. The stable oxygen isotope ratio (δ18O) of plant cellulose can be used to resolve a photosynthesis-weighted estimate of canopy temperature, but the method requires independent confirmation. We compare isotope-resolved canopy temperatures derived from multi-year homogenization of tree cellulose δ18O to canopy-air temperatures weighted by gross primary productivity (GPP) at multiple sites, ranging from warm temperate to boreal and...AuthorsBrent R. Helliker, Xin Song, Michael L. Goulden, Ken Clark, Paul Bolstad, J. William Munger, Jiquan Chen, Asko Noormets, David Hollinger, Steve Wofsy, Timothy Martin, Dennis Baldocchi, Eugenie Euskirchenn, Ankur Desai, Sean P. BurnsKeywordsSourceOecologiaYear2018
- Background: United States forests can contribute to national strategies for greenhouse gas reductions. The objective of this work was to evaluate forest sector climate change mitigation scenarios from 2018 to 2050 by applying a systems- based approach that accounts for net emissions across four interdependent components: (1) forest ecosystem, (2) land-use change, (3) harvested wood products, and (4) substitution benefits from using wood products and bioenergy. We assessed a range of land management and harvested wood product scenarios for two case studies in the U.S: coastal South Carolina...AuthorsAlexa J. Dugan, Richard Birdsey, Vanessa S. Mascorro, Michael Magnan, Carolyn E. Smyth, Marcela Olguin, Werner A. KurzKeywordsSourceCarbon Balance and ManagementYear2018
- If forest landscape restoration (FLR) aims towards living sustainably within landscapes and restoring degraded socio-ecological systems, then integrating lessons of Traditional and Western knowledge systems can inform this effort (c.f. Ruiz-Mallen and Corbera, 2013). Knowledge systems represent much more than repositories of timeless information useful to today's managers and restorationists: they are intricately coupled human and natural systems that have evolved through intergenerational and community-based stewardship of natural resources. In this context, Berkes (2007) cautions that...AuthorsFrank K. Lake, Christian P. Giardina, John A. Parrotta, I. Hunt-DavidsonKeywordsSourceForest Landscape Restoration: Integrated approaches to support effective implementationYear2018
- Remote sensing data have increasingly been employed in combination with field plot data to estimate aboveground carbon (C) stocks across heterogeneous forested landscapes around the world. The Forest Inventory and Analysis (FIA) program of the US Forest Service offers a gridded network of field plots which potentially can be linked to airborne Light Detection and Ranging (LiDAR) data to estimate forest aboveground carbon density (ACD; units of Mg C ha−1). Here we utilized FIA plot and airborne LiDAR data sets collected across two contrasting landscapes known as Laupahoehoe and Pu‘u...AuthorsFlint F. Hughes, Gregory P. Asner, Jim Baldwin, Joseph Mascaro, Lori Bufil, David E. KnappKeywordsSourceForest Ecology and Management. 424: 323-337Year2018
- Solar-induced chlorophyll fluorescence (SIF) has been increasingly used as a proxy for terrestrial gross primary productivity (GPP). Previous work mainly evaluated the relationship between satellite-observed SIF and gridded GPP products both based on coarse spatial resolutions. Finer resolution SIF (1.3 km × 2.25 km) measured from the Orbiting Carbon Observatory-2 (OCO-2) provides the first opportunity to examine the SIF–GPP relationship at the ecosystem scale using flux tower GPP data. However, it remains unclear how strong the relationship is for each biome and whether a robust, universal...AuthorsXing Li, Jingfeng Xiao, Binbin He, M. Altaf Arain, Jason Beringer, Ankur R. Desai, Carmen Emmel, David Hollinger, Alisa Krasnova, Ivan Mammarella, Steffen M. Noe, Penélope Serrano Ortiz, A. Camilo Rey-Sanchez, Adrian V Rocha, Andrej VarlaginKeywordsSourceGlobal Change BiologyYear2018
- The large, highly glacierized Copper River basin is an important water resource for the south-central region of Alaska. Thus, information is needed on the reaction of its hydrologic timing and streamflow volumes to historical changes in climate, in order to assess the possible impact of future changes. However, the basin is remote, and therefore, it has proved difficult to collect field data in a frequent temporal and spatial manner. An extension of the distributed-parameter, physical-process code Precipitation Runoff Modeling System, PRMSglacier, has been specifically developed to...AuthorsAshley Van Beusekom, Roland J. VigerKeywordsSourceWater Resources ResearchYear2018
- Changing climate will impact species’ ranges only when environmental variability directly impacts the demography of local populations. However, measurement of demographic responses to climate change has largely been limited to single species and locations. Here we show that amphibian communities are responsive to climatic variability, using >500,000 time-series observations for 81 species across 86 North American study areas. The effect of climate on local colonization and persistence probabilities varies among eco-regions and depends on local climate, species life-histories, and taxonomic...AuthorsDavid A. W. Miller, Evan H. Campbell Grant, Erin Muths, Staci M. Amburgey, Michael J. Adams, Maxwell B. Joseph, J. Hardin Waddle, Pieter T. J. Johnson, Maureen E. Ryan, Benedikt R. Schmidt, Daniel L. Calhoun, Courtney L. Davis, Robert N. Fisher, David M. Green, Blake R. Hossack, Tracy A. G. Rittenhouse, Susan C. Walls, Larissa L. Bailey, Sam S. Cruickshank, Gary M. Fellers, Thomas A. Gorman, Carola A. Haas, Ward Hughson, David S. Pilliod, Steven J. Price, Andrew M. Ray, Walt Sadinski, Daniel Saenz, William J. Barichivich, Adrianne Brand, Cheryl S. Brehme, Rosi Dagit, Katy S. Delaney, Brad M. Glorioso, Lee B. Kats, Patrick M. Kleeman, Christopher A. Pearl, Carlton J. Rochester, Seth P. D. Riley, Mark Roth, Brent H. SigafusKeywordsSourceNature CommunicationsYear2018
- Eddy covariance methodologies have greatly improved our understanding of the forest carbon cycle, including controls over year-to-year variability in productivity (measured as net ecosystem productivity, NEP, where NEP is the difference between the mass of carbon fixed by photosynthesis and that lost by ecosystem respiration). However, establishing and maintaining eddy covariance towers requires sizeable financial and logistical investments. Tree-ring methods, which can produce annual estimates of tree biomass increment from individual trees, provide an alternative approach for assessing...AuthorsAaron Teets, Shawn Fraver, David Hollinger, Aaron R. Weiskittel, Robert S. Seymour, Andrew D. RichardsonKeywordsSourceAgricultural and Forest MeteorologyYear2018
- Despite decades of research, gaining a comprehensive understanding of carbon (C) cycling in forests remains a considerable challenge. Uncertainties stem from persistent methodological limitations and the difficulty of resolving top-down estimates of ecosystem C exchange with bottom-up measurements of individual pools and fluxes. To address this, we derived estimates and associated uncertainties of ecosystem C fluxes for a 100–125 year old mixed temperate forest stand at the Bartlett Experimental Forest, New Hampshire, USA, using three different approaches: (1) tower-based eddy covariance,...AuthorsAndrew P. Ouimette, Scott V Ollinger, Andrew D. Richardson, David Hollinger, Trevor F. Keenan, Lucie C. Lepine, Matthew A. VadeboncoeurKeywordsSourceAgricultural and Forest MeteorologyYear2018