Treesearch

Selective logging, fire suppression, forest succession, and climatic changes have resulted in high fire hazards over large areas of the western USA. Federal and state hazardous fuel reduction programs have increased accordingly to reduce the risk, extent and severity of these events, particularly in the wildland urban interface. In this study, we examined the effect of mechanical fuel reduction treatments on the activity of bark beetles in ponderosa pine, Pinus ponderosa Dougl ex. Laws., stands located in Arizona and California, USA. Treatments were applied in both late spring (April-May)...

Bitterbrush (Purshia tridentata) and mahala mat (Ceanothus prostratus) are common N-fixing shrubs in interior forests of the western United States, yet their contribution to ecosystem N pools is poorly characterized. We compared N fixation and soil N accretion by these shrubs in old-growth ponderosa pine (Pinus ponderosa) -- Jeffrey pine (Pinus jeffreyi) stands versus stands that had been harvested 50 years earlier. No differences (Alpha = 0.10) in cover, biomass, or percent N derived from fixation by bitterbrush or mahala mat were found between harvested and uncut stands. Approximately...

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This paper compares stand characteristics of Old Growth coastal redwood stand densities and forest structure found throughout the northern tier of the range of coast redwood (Sequoia sempervirens). Tree densities are relatively low compared to commercially managed stands of coast redwood. Tree size classes distributions vary from 254cm (2" dbh to >100��). Dominant tree species include tanoak (Lithocarpus multiflora), Douglas-fir (Psuedotsuga menzisii) and Coast Redwood (Sequoia sempervirens). Snag densities are given for a stand of old-growth redwoods in Mendocino County.

Recently regenerated mesic sites in the southern Appalachian Mountains often provide poor brooding areas for wild turkey (Meleagris gallopavo) because shade from thick stands of hardwood saplings reduces cover of herbaceous vegetation and the accompanying insects that provide the essential protein needed by young poults. An operational prescribed fire was used to reduce density of 5-yr-old hardwood regeneration on an east-facing cove site that was dominated by saplings of yellow-poplar (YP) (Liriodendron tulipifera L.), a mesophytic, shade-intolerant species that regenerates readily from...

In 2001, the state of California initiated the North Coast Watershed Assessment Program (2003a) to assemble information on the status of coastal watersheds that have historically supported anadromous fish. The five-agency consortium explored the use of Ecosystem Management Decision Support (EMDS) (Reynolds and others 1996) as a means to help assess overall watershed and in-stream conditions for fish. EMDS is expert system software developed by the USDA Forest Service for similar efforts with the Northwest Forest Plan (2000). NCWAP developed models to help assess key watershed characteristic...

Fish habitat in cold water streams in many northwestern California watersheds has been declared degraded under provisions of the Federal Clean Water Act, contributing to listings of anadromous fish species under the Endangered Species Act. It is believed that past and present land management activities induce erosion that contributes excess sand-size and finer sediment to stream systems, which then causes an increase in the proportion of fine sediment in spawning gravels. The higher proportion of fine sediment can reduce the rate of survival of eggs. Target thresholds for desirable fine...