Recent climatic warming trends and increases in the frequency and extent of wildfires have prompted much concern regarding the potential for rapid change in the structure and function of forested ecosystems around the world. Episodes of mortality in wildfires and insect outbreaks associated with drought have affected large areas and...
The structure and composition of mixed-conifer forest (MCF) in central Oregon has been altered by fire exclusion and logging. The resulting increased density, spatial contagion, and loss of fire resistant trees decrease the resiliency of this ecosystem to fire, drought, and insects. The historical and current composition and structure of...
Though the mixed-evergreen forests of the Klamath Siskiyous have a long history of large, mixed-severity fires, most research in this region has concentrated on the impacts of high-severity fire. Knowledge of the ecological effects of low- and moderate-severity areas within mixed-severity fires is important because such areas may account for...
The forest alpine tundra ecotone (FTE, also known as alpine treeline or subalpine parkland), is a conspicuous feature of mountain landscapes throughout the world. Climate change-driven increases in temperature are believed to result in FTE movement and tree invasion of subalpine meadows, which have been documented throughout the Northern Hemisphere...
Effects of small-scale disturbances on fecundity and growth rates of Linnaea
borealis L., Tiarella trifoliata L. var. unifoliata, and Trillium ovatum Pursh. were studied in
old-growth forests in the Tsuga heterophylla Zone on the west slope of the Cascade
Mountain Range of Oregon. Performance of each species was compared in...
Knowledge about vegetation patterns and ecological processes in unmanaged, late-successional
watersheds is needed to provide a foundation for forest management strategies
aimed at conserving native biodiversity. I examined influences of environmental variability
and disturbance history on forest structure and composition in the Cummins Creek
Wilderness, located on the central Oregon...
History is an invaluable source of information to understand and evaluate management influences on contemporary ecosystems and landscapes. The first two chapters (Chapters 2 and 3) explored the concept of historical range of variability (HRV) in landscape structure and stand structure using a stochastic fire simulation model to simulate presettlement...
We have a poor understanding of the biotic communities in zero-order basins, drainages extending from ridgelines to the initiation of first-order streams. This study describes baseline plant and amphibian composition in unmanaged zero-order basins in the Oregon Coast Range. Specifically, I studied: i) the spatial distribution and diversity of species,...
Dead wood patterns and dynamics vary with biophysical factors, disturbance history, ownership, and management practices. Through field and modeling studies, I examined the current and potential future amounts of dead wood in two landscapes and region-wide in the Coastal Province of Oregon. The objectives of the first study were to...
Trees that survive disturbances can form a prominent legacy which may influence
post-disturbance successional pathways. The effects of biological legacies on community
dynamics is a critical question in ecology. In the present study, I examined two mapped
stands in which old-growth remnant trees, survivors of partial fires, emerge above a...
