Atmospheric carbon dioxide levels have been steadily increasing from anthropogenic energy production, development and use. Carbon cycling in the terrestrial biosphere, particularly forest ecosystems, has an important role in regulating atmospheric concentrations of carbon dioxide. US West coast forest management policies are being developed to implement forest bioenergy production while...
Earth’s atmosphere is unequivocally warming due to CO₂ and other greenhouse gas (GHG) emissions from human activities and this is having widespread impacts on forest ecosystems that provide important services to human societies. Forest ecosystems help regulate atmospheric CO2 concentrations by sequestering carbon in tree biomass and soils, which is...
Net uptake of carbon from the atmosphere (net ecosystem production, NEP) is dependent on climate, disturbance history, management practices, forest age, and forest type. To improve understanding of the influence of these factors on forest carbon flux in the western U.S., a combination of federal inventory data and supplemental ground...
Fire is a fundamental disturbance that drives terrestrial and atmospheric carbon dynamics. Previous studies have quantified fire effects on carbon cycling from local to global scales but have focused nearly exclusively on high-severity, stand-replacement fire. Since 2002, variable-severity wildfires have burned more than 65 000 ha across the east slope...
Methods for obtaining accurate, spatially explicit estimates of biomass density in tropical forests are required to reduce uncertainties in the global carbon cycle, and to support international climate agreements and emerging carbon markets. Three-dimensional (3-D) remote sensing techniques sensitive to the vertical structure of vegetation provide a unique opportunity for...
Following high-severity fire, forest succession may take alternate pathways depending on the pattern of the fire and any secondary disturbances during early stand development, with lasting consequences for ecosystem function. The objectives of this research were to quantify: (1) early postfire regeneration as influenced by the spatial pattern of a...
In this study we use a combination of data from forest inventories,
intensive chronosequences, extensive sites, and remote sensing, to make estimates
of biomass and net primary production (NPP) for the forested region of Western
Oregon. Plot-level forest inventory data were provided by the USDA Forest
Service through their Forest...
Water treatments were applied to young ponderosa pine trees in the Eastern Cascades, Oregon during the 2003 growing season, and shade treatments were applied during the 2003 and 2004 growing seasons to understand how photosynthesis and soil respiration, particularly the root/rhizosphere fraction (R[subscript rrh]), would respond to increased moisture availability...
In order to investigate potential climate impacts on landscape-scale ecosystem processes, I implemented a dynamic general vegetation model (DGVM) over a large domain in northern California and western Nevada on a rectangular grid of ca. 800-meter spatial resolution. I used 100 years of observed, monthly climate and nine future climate...
The U.S Pacific Northwest contains a wide variety of ecosystems, all subject to relatively dry summers and wet winters. As has been shown with paleoclimatic and paleoecological data, the region is vulnerable to changes in climate. We assessed the sensitivities of vegetation distributions, carbon stocks, and fire regimes to 21st...
