Treesearch

Home ranges of 14 pairs of spotted owls (Strix occidentalis) were studied over four to six seasons in three southwest Oregon landscapes that differed in prey base and degree of forest fragmentation. The general theory of space use and the biology of spotted owls was used to construct a scheme for spatiotemporal analyses that provided insights beyond those possible with polygon home-range methods. Landscape units, precisely defined by habitat type and aspect, were classified as not used, used ¡Üexpected based on area, and used > expected (selected). Selected units were categorized further...

An old-strucutre stand with large amounts of tree mortality was treated to accelerate regeneration and reduce fuel loads but still maintain its function as old growth for selected bird species. The small-diameter (

1. We examined how rapidly soils can change during secondary succession by observing soil development on 350-year chronosequences in three pristine forest ecosystems in south-east Alaska. 2. Soil surfaces, created by different windthrow events of known or estimated age, were examined within each of three forest stands (0.5-2.0 ha plots; i.e. a within-stand chronosequence method). Soil surfaces are more likely to have developed under common climate and vegetation conditions within stands than in the spatially separated ecosystems used in traditional chronosequence studies. 3. We observed...

To monitor consequences of past operational practices, we installed eight 0.05-acre plots in a 9-year-old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) plantation established after clearcutting a grossly overstocked stand on a poor-quality site. Logging slash was broadcast burned on half this clearcut. One plot sampled the slash-burned portion, and seven sampled the nonburned portion. Of these, two were in areas thinned 3 years earlier by machete combined with pulling smaller seedlings four were in areas thinned by chainsaw, and one was in a nonthinned strip. Depending...

Growth and mortality in a ponderosa pine (Pinus ponderosa Dougl. ex Laws.) stand were investigated for 24 years. High mortality rates from mountain pine beetle (Dendroctonus ponderosae Hopkins) occurred on some plots where values for stand density index exceeded 140. Periodic annual increments for quadratic mean diameters decreased curvilinearly as stand density increased, whereas periodic annual increments of gross basal area and gross cubic volume increased curvilinearly with increasing stand density. Cubic volume yield at a stand age of 84 years increased linearly with increasing...

We investigated the distribution of biomass and nutrients in second-growth ponderosa pine (Pinus ponderosa Dougl. ex Laws.) ecosystems in central Oregon. Destructive sampling of aboveground and belowground tree biomass was carried out at six sites in the Deschutes National Forest; three of these sites also were intensively sampled for biomass and nutrient concentrations of the soil, forest floor, residue, and shrub components. Tree biomass equations were developed that related component biomass to diameter at breast height and total tree height. No significant differences in equation...

Tree numbers, height, and volume were determined in six 63- to 66-year-old plantations of coast Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) in northwest Washington. These stands resulted from the first extensive plantings of this species in the Pacific Northwest. Data from 0.25-acre plots in these plantations were compared to those from matched plots in adjacent, naturally regenerated stands with the same history of logging, wildfire, and absence of further silviculture after regeneration. Planting resulted in well-stocked Douglas-fir stands with volunteers of other...

Dendroecology methods were used to reconstruct a three-century history of western spruce budworm and Douglas-fir tussock moth outbreaks in the Blue Mountains of northeastern Oregon. Comparisons of 20th century Forest Service documentary records and host and nonhost tree-ring width chronologies provided an objective basis for distinguishing climatic effects from insect-caused defoliation effects. Budworm outbreaks were more confidently reconstructed than were tussock moth outbreaks. Since A.D. 1700, at least eight regional budworm outbreaks have occurred at intervals of about 21 to 53...

Forest managers in the Pacific Northwest are faced with new challenges of providing for all wildlife in managed forests. Our objective was to elucidate the factors governing the composition and biomass of forest floor mammal communities that are amenable to management. We sampled small mammal communities in forests of various management histories on the Olympic Peninsula and contrasted our results with those of other large studies in the Pacific Northwest. Forest floor mammal communities in forests >35 yr old in the Western Hemlock Zone of Washington and Oregon are composed of 5-8 character...

Implications of the interim comprehensive strategy for improved Pacific salmon and steelhead habitat management (PACFISH) were estimated for those Bureau of Land Management (BLM) districts and National Forest System (NFS) lands west of the Rocky Mountains that have anadromous fish. The physical impacts and associated mitigation costs from implementing the PACFISH strategy over the the next decade in Pacific Northwest, Intermountain, Northern, Pacific Southwest, and Alaska Region National Forest and BLM district recreation, range, and timber programs were analyzed with the actual current...