Protracted drought in the southwest U.S. has had significant impacts on the region’s keystone ecosystem, the pinyon-juniper (PJ) woodlands. Drought conditions in 9 of the last 10 years, exacerbated by extreme drought in one year, stressed the pinyon pine (Pinus edulis) trees, making them highly vulnerable to native ips beetles...
Accurate estimation of live and dead biomass in forested ecosystems is important for
studies of carbon dynamics, biodiversity, and wildfire behavior, and for forest management.
Lidar remote sensing has been used successfully to estimate live biomass, but studies focusing
on dead biomass are rare. We used lidar data, in conjunction...
Despite holding substantial ecological value, wetlands in the United States have experienced a significant decline in both area and function over the past century with the majority of freshwater wetland loss attributed to agricultural conversion. Agriculture is the second largest industry in the State of Oregon and the State places...
Improved monitoring of forest biomass is needed to quantify natural and anthropogenic effects on the terrestrial carbon cycle. Landsat's temporal and spatial coverage, fine spatial grain, and long history of earth observations provide a unique opportunity for measuring biophysical properties of vegetation across large areas and long time scales. However,...
The use of Landsat data has historically been constrained to spectral and spatial information derived from a carefully selected image or set of images. However, free and open access to Landsat imagery combined with advances in data storage and computing are revolutionizing how the Landsat temporal domain is used to...
Spatially explicit maps of habitat relationships have proven to be valuable tools for conservation and management applications including evaluating how and which species may be impacted by large scale climate change, ongoing fragmentation of habitat, and local land-use practices. Studies have turned to remote sensing datasets as a way to...
To effectively study dynamic processes like forest succession over long time periods one must effectively integrate data collected at many different times, locations and spatial scales. The purpose of this research is to integrate forest inventory data collected by the USDA Forest Service’s Forest Inventory and Analysis (FIA) Program with...
Accurate estimates of forest aboveground biomass are needed to reduce uncertainties in the terrestrial carbon flux. The Geoscience Laser Altimeter System (GLAS) onboard the Ice, Cloud and land Elevation Satellite is now the first spaceborne lidar sensor that will provide global estimates of vegetation height. This study investigated the utility...
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WarrenB. Cohen
Accurate estimates of forest aboveground biomass are needed to reduce
Human activities are causing profound changes to the global environment, yet the potential consequences of these changes on rising atmospheric carbon dioxide and climate change are not well understood. Improving our understanding of these processes requires an enhanced awareness of how global ecosystems are changing and how these changes affect...
The Earth’s surface is experiencing unprecedented change. Humanity’s growing population, expanding land-use footprint, and increasing global emissions of atmospheric greenhouse gases affect a vast number of species on Earth and the functioning of virtually all ecosystems. Given the vital interactions and feedbacks between the Earth’s land surface and climate, measurements...