The Tualatin Basin landscape has undergone extensive change since the initiation of Euro-American settlement, with important consequences for basin hydrology and water quality. Changes that include the isolation of the Tualatin River from its floodplain areas, losses of important wetlands and riparian areas, and urbanization associated with population growth in...
Fire history and fire regime were interpreted from tree ring analysis of 4320 stumps at 178 sites in a 25 by 55 km area in the central Oregon Coast Range. A total of 27 fire episodes were identified in a 516 year period, with sizes estimated at 18 to 544...
The Rattlesnake Ash-Flow Tuff erupted 7.05±0.01 Ma from the western Harney Basin, southeastern Oregon. The location of the vent area is inferred based on vent-ward increases in size of pumices, in degree of welding, and in degree of post-emplacement crystallization. Today's outcrops cover 9000 km2 and estimated original outcrop coverage...
The lower Columbia River (LCR) riparian zone is rich in habitat diversity. However, the natural beauty and species diversity along the river have increasingly become affected by human activity. This study quantifies the areal extent and degree of wetlands change and associated causes along the LCR over the past 44...
The Calvin impact crater is an isolated, nearly circular subsurface structure of Late
Ordovician age in southwestern Michigan. The crater is defined by 110 on and gas test wells, has a rim to rim diameter of 6.2 km, an overall dimensional diameter of 8.5 km and
consists of a central...
River regulation imposes changes in the supply of sediment and the frequency of competent flows. As a result, impounded rivers often exhibit downstream changes in channel processes, particle size, and morphology. The magnitude of change in competent flow frequency and sediment load together can be used to predict the pattern...
The Absaroka volcanic province is the largest of Eocene volcanic fields in the northern Cordillera of the western U.S., and consists of 25,000 km2 of lava flows, shallow intrusions, ash-flow tuffs and volcaniclastic deposits. It is aligned with northwest-trending Precambrian lineaments, and includes the remains of at least ten volcanic...
Few landscapes are immune to invasion by exotic plant species. The forested landscape in the western Cascade Range of Oregon appears to have some barriers to invasion, but the extensive road network provides a corridor and habitat for a suite of exotic species to enter and become established. This study...
The diffusion of livestock guarding dogs into American agriculture provides an example of a developed nation adopting a peasant husbandry practice. Guarding dogs, associated with transhumant husbandry, have been used to protect sheep and other livestock from predators in Eurasia for 2000 years. However, they were virtually unknown by Anglo-American...
The Central Western Cascades and southeast Zaire were selected to test the distance decay and deforestation models on forest environments. Distance gradients included away from cities, and away from highways/roads. Two forest definitions were used in each study site. The "extended-forest" definition included areas with at least 30 percent canopy...