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...
Pinyon-juniper woodlands throughout the western U.S. have expanded rapidly following European settlement during the late 19th century. In central and eastern Oregon, western juniper (Juniperus occidentalis var. occidentalis Hook.) encroachment has been previously documented in the sagebrush steppe and upper elevation aspen communities. While these vegetation changes and dynamics have...
Weed control in Pacific Northwest forests has been criticized for its potential impact on biodiversity. Changes were evaluated in conifer growth, diversity of vegetation in situ and of recruiting plants through different regeneration mechanisms after applying temporally-varied weed control by herbicide treatments based on the critical period concept. Conifer size...
An accuracy assessment of two broad-scale vegetation databases for eastern Oregon, both developed from satellite imagery, was performed to assess the usefulness of the databases for forest landscape planning and assessment efforts. The two databases were the Oregon Department of Forestry (ODF) vegetation database and the U.S. Geological Survey National...
Since European American settlement of the Intermountain Region, dramatic changes in vegetation composition and structure have occurred in the sagebrush steppe ecosystem. Western juniper (Juniperus occidentalis spp. occidentalis Vasek), although indigenous to the Intermountain Region, has increased since the late 1800s. Considerable work has been done documenting juniper woodland expansion...
Fire is the dominant disturbance process in western U.S. forests, and although effects of fire in upland forests are relatively well-studied, there is little information about fire effects on riparian forests, critical areas of the landscape for both habitat and water quality. This dissertation examines different aspects of fire effects...