Treesearch

We examined the process of fragmentation in a managed forest landscape by comparing rates and patterns of disturbance (primarily clear-cutting) and regrowth between 1972 and 1988 using Landsat imagery. A 2589-km2 managed forest landscape in western Oregon was classified into two forest types, closed-canopy conifer forest (CF) (typically, > 60% conifer cover) and other forest and nonforest types (OT) (typically, < 40 yr old or deciduous forest). the percentage of cf declined from 71 to 58% between 1972 and 1988. declines were greatest on private land, least in wilderness, and intermediate...

Natural disturbances are important to ecosystem processes. Disturbances historically have occurred in the vegetation of the Blue Mountain area of northeastern Oregon and southeastern Washington. The primary modifying events that historically have cycled through most of its plant communities are fire, grazing and browsing, insect and disease epidemics, windthrow, flooding, and erosion. Knowledge of plant successional pathways enables managers to predict the probable course of community development for a disturbance regime. Recommendations for restoring the Blue Mountains area are to...

Patterns of development of mean annual increment in relation to age predicted by the widely used DFSIM, SPS, TASS, and ORGANON simulators were examined. Although predictions differ considerably among simulators for portions of the range of sites, ages, and treatments, comparisons indicated that (1) culmination is relatively late, (2) the curve is relatively flat in the vicinity of culmination, and (3) systematic thinning tends to delay culmination. Harvest ages of 40 to 50 years reduce volume production relative to potential by amounts ranging from moderate to large according to site,...

Adaptive genetic variation in seed and seedling traits was evaluated for 280 families from 220 locations. Factor scores from three principal components were related by multiple regression to latitude, longitude, elevation, slope, and aspect of the seed source, and by classification analysis to seed zone and elevation band in seed zone. Location variance was significant but not large. Multiple regression equations explained less than 50 percent of location variance. Slope-aspect variables were important.

Adaptive genetic variation in seed and seedling traits for ponderosa pine from the east slopes of the Cascade Range in Oregon was analyzed by using 307 families from 227 locations. Factor scores from three principal components based on seed and seedling traits were related by multiple regression to latitude, distance from the Cascade crest, elevation, slope, and aspect of the seed source and by classification analysis to seed zone and 300-meter elevation band within zone. A provisional transfer risk equation and tentative new seed zones were delineated to guide seed transfer in artificial...

Portions of forest ecosystems in eastern Oregon and Washington are in poor health, are not meeting societies expectations, and have elevated hazard for fire, insects, and disease. Diversity in stream habitats and associated fisheries has declined over the last several decades in several drainage basins, requiring conservation and restoration efforts in key watersheds. Required first steps in restoring forest and aquatic ecosystems are the immediate reduction in hazard for catastrophic loss of biodiversity, site quality, resource commodities, and improved conditions for public health. To...

Procedures for monitoring larval populations of the Douglas-fir tussock moth and the western spruce budworm are recommended based on many years experience in sampling these species in eastern Oregon and Washington. It is shown that statistically reliable estimates of larval density can be made for a population by sampling host trees in a series of permanent plots in a geographical monitoring unit. The most practical method is to estimate simultaneously densities on a plot of both insect species by the nondestructive sampling of foliage on lower crown branches of host trees. This can be...

Productivity of forest and range land soils is based on a combination of diverse physical, chemical and biological properties. In ecosystems characteristic of eastside regions of Oregon and Washington, the productive zone is usually in the upper 1 or 2 m. Not only are the biological processes that drive both soil productivity and root development concentrated in limited organic horizons, but also they have evolved historically in a natural system that includes mostly modest surface disturbance. Typical disturbances include erosional, seismic, or tip-over events, and modest surface heating...

Traces the natural and cultural processes involved in shaping the environment in the intermontane northwest from the Indian period of domination to the present. Emphasizes the increasing influence of humans as modifiers of landscapes and ecosystems, especially with the coming of the market system to the region and the onset of the industrial era. Focuses on the unique aspects of ecological change in the intermontane region: the very recent extension of the market system to the area; and the very rapid expansion of human-induced environmental disturbance over very extensive areas in a very...

New approaches and technologies to evaluate wildlife-habitat relations, implement integrated forest management, and improve public participation in the process are needed to implement ecosystem management. Presented here are five papers that examine ecosystem management concepts at international, national, regional, and local scales. Two general management problems were addressed: how to incorporate different components of ecosystem management into specific forestry and wildlife management practices, and how to resolve conflicts and involve citizens more effectively in the management...