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...
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...
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...
The MODIS NBAR (M0D43B4) data space is explored in terms of biophysical variables with the objective of formulating a MODIS transformation relevant to global vegetation studies. The basic ideas of transform formulation were borrowed from the development of the TM Tasseled Cap transformation, but with differences in sampling strategy and...
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
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...
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...
When biogeochemical models are applied to large regions, the values of key model parameters are often unknowable. Through field and modeling studies, I examined the potential impact of such uncertainty on estimates of carbon cycling in western Oregon. I found that variation in key leaf traits could be interpreted ecologically,...
Historical aerial photos were used to examine the early phase of forest succession after stand replacement disturbance, covering the Coast Ranges Province (CRP) and the western Cascades Province (WCP) of western Oregon. The study consisted of two components: characterizing the pattern of forest succession in western Oregon; analyzing the influence...
The hump-shaped relationship that predicts highest species richness (species/unit area) at intermediate levels of productivity was examined for woody plants across the Pacific and Inland Northwest of the U.S. Many studies have examined this relationship at regional scales, but commonly use species range maps and surrogate measures of productivity (e.g....
