Treesearch

Timber harvesting is one of the most widespread land-uses in forested watersheds throughout western North America. It has long been recognized that timber removal, primarily through clearcutting, may have significant impacts on some environmental conditions within streams draining forested watersheds. It is also clear that logging related impacts are highly variable among streams from different regions, primarily due to varying influences of climate, geology and forest type.

Following fires in the forested ecosystems of the northern Sierra Nevada, California, early successional communities are often dominated by shrubs that arise from seeds that have remained viable in soil seedbanks for long periods. The germination response of seeds of three seral montane shrub species was investigated following exposure to differing types of heat (wet vs. dry), temperatures, duration of temperature exposure, and differing stratification periods. The highest germination (>60%) of Ceanothus integerrimus was observed for seeds scarified by wet heat at 75-100°C; for 4-8...

Group selection openings ranging from 0.1 to 2.0 acres in mixed conifer stands in northern and central California were evaluated for effect of site preparation, opening size, kind and amount of vegetation, and release treatment. Small openings, in general, are characterized by less sunlight and lower temperature extremes than clearcuttings. Roots from border trees extend into openings and apparently capture a large amount of site resources. Site preparation is needed for establishment of natural conifer regeneration, but seldom for establishment of planted seedlings. Survival of conifer...

Surveying and mapping work has been an essential and time consuming part of the Caspar Watershed study during the North Fork phase. The cumulative effects study and several other studies being done in this phase require accurate mapping and periodic map updating of watershed features and disturbances.

As part of the ongoing Caspar Creek Watershed Study on Jackson Demonstration State Forest, researchers from the US Forest Service and the California Department of Forestry and Fire Protection are investigating subsurface drainage in the headwaters of the basin. In order to predict how land use practices will impact stream systems, and hence habitats for aquatic organisms, we must develop an understanding of how water and sediment move down to the channel system. Subsurface flows are the primary source of stormflow in this region, where hillslopes are often prone to land slides.

Abstract - Since 1962, the 483-ha North Fork and 424-ha South Fork of Caspar Creek in northwestern California have been used to evaluate the hydrologic impacts of road building and harvesting second-growth redwood/Douglas-fir forests. Three tributaries are serving as untreated controls. In 1985, the study was modified to evaluate the cumulative watershed effects of logging the North Fork. Intensively measured were precipitation, soil moisture, groundwater, subsurface pipeflow, streamflow and suspended sediment discharge at 15 gauging stations, bedload movement, stream channel stability,...

Abstract - It is impractical to address the long-term effect of forest management strategies on erosion, sedimentation, and the resultant damage to fish habitat experimentally because to do so would require studying large watersheds for a century or more. Monte Carlo simulations were conducted on three hypothetical 10 000 ha, fifth-order forested watersheds. One watershed was left undisturbed, one was completely clearcut and roaded in a decade, and one was cut at the rate of 1% each year. Each cutting strategy was repeated in succeeding centuries

Abstract - There is increasing concern over the possibility of adverse cumulative watershed effects from intensive forest management. It is impractical to address many aspects of the problem experimentally because to do so would require studying large watersheds for 100 yr or more. One such aspect is the long-term effect of forest management strategies on erosion and sedimentation and the resultant damage to fish habitat. Is dispersing activities in time and space an effective way to minimize cumulative sedimentation effects? To address this problem, Monte Carlo simulations were conducted...

Cumulative Watershed Effects (CWEs) may be additive or synergistic. Additive CWEs are the accumulation downstream of the effects of various activities. Their existence is inevitable. However, their magnitude is often difficult to measure. The amount of sediment, for example, has considerable natural variation which may mask the CWEs caused by road construction or forest roads. Synergistic CWEs present still more difficult measurement problems. They are based on the idea that even though Best Management Practices (BMPs) are being applied, somewhere downstream their effects may aggregate in...

Terrestrial and aquatic herpetofauna were sampled by three methods, time-constrained searches, pitfall traps, and areaconstrained searches from 1984 to 1986 in northwestern California and southwestern Oregon. The 54 terrestrial and 39 aquatic study sites were in Douglas-fir/hardwood forest stands that ranged in age from 30 to 560 years. Results of these surveys are presented in terms of species richness, equitability, relative abundance, relative biomass, and macrohabitat and microhabitat associations. Although species richness did not differ among forest ageclasses, the composition of the...