Treesearch

Timber harvest practices must address potential impacts to aquatic and riparian habitats. Stream shading and cool water temperature regimes are important to protect stream-dwelling organisms. We are examining riparian temperature regimes within the coastal redwood area of Mendocino County. Summer temperature gradients are being characterized along fifteen transects set perpendicular to watercourses within four different watersheds. Data loggers record temperature along each transect at predetermined spatial intervals from the watercourse midpoint. With the exception of a control transect,...

Within the second-growth redwood forest of the Caspar Creek watershed, fog drip was measured in 1998 at 12 sites where heavy fog drip was expected. The following year, two one-ha plots were each instrumented with six randomly sited 1.35 m2 fog-drip collectors and one additional collector in a nearby clearcut. Fog-drip totals were highly variable, ranging from zero to 18 mm per event (mean = eight mm) and 0.2 to 99 mm (mean = 39 mm) during the 1999 season. Within the one-ha plots, fog drip under the canopy was only three mm greater than accumulations in the clearcut at one site and not...

Streamflow and suspended sediment were intensively monitored at fourteen gaging stations before and after logging a second-growth redwood (Sequoia sempervirens) forest. About 50 percent of the watershed was harvested, primarily by clear-cutting with skyline-cable systems. New road construction and tractor skidding were restricted to gently-sloping ridge top locations, and watercourse protections were enforced. Storm peak flows increased as much as 300 percent in clear-cut watersheds, but as antecedent wetness increased, percentage increases declined. In the first five to seven years after...

Throughfall was measured for a year at five-min intervals in 11 collectors randomly located on two plots in a second-growth redwood forest at the Caspar Creek Experimental Watersheds. Monitoring at one plot continued two more years, during which stemflow from 24 trees was also measured. Comparison of throughfall and stemflow to rainfall measured in adjacent clearings indicates throughfall and stemflow accounted for 75.1 and 2.5 percent, respectively, of annual rainfall, while 22.4 percent was intercepted and evaporated by the forest canopy. Average interception loss remains above 20...

Demand for wood products and advances in logging technology post-World War II resulted in timber harvesting that extensively modified streams on the North Coast of California. To assess the resulting impacts to salmonid populations, the Department of Fish and Game conducted studies at widely spaced sites throughout the redwood region during the 1960s. In order to compare current salmonid communities with those documented earlier, we resumed investigations on the South Fork, Caspar Creek in 1993. During the last decade, total salmonid density was within the range observed during the 1960s,...

Regeneration of coast redwood by stump sprouting often results in a stand condition that is very dense. A precommercial thinning of redwood sprouts allows managers to select trees and spacing that can best utilize the productivity of the site. The study of five thinning treatments with an unthinned control was initiated on a 19-year old third growth stand. Treatments were 100, 150, 200, 250, and 300 trees per acre plus an unthinned control. All 18 plots were measured in 1981 immediately after precommercial thinning, again in 1986 (5-year growth), and again in 1998 (12-year growth). Results...

In constructing management models for the control of sediment delivery to streams, we have used a simulation model of road surface erosion known as the Watershed Erosion Prediction Project (WEPP) model, developed by the USDA Forest Service. This model predicts discharge, erosion, and sediment delivery at the road segment level, based on a stochastic climate simulator and road segment characteristics. To apply the WEPP model, we collected data on road segment dimensions, design and slope for 57 contiguous road segments totaling 3.5 miles of Road 630 on the Jackson Demonstration State...

Variable retention is a flexible silvicultural system that provides forest managers with an alternative to clearcutting. While much of the standing volume is removed in one harvesting operation, residual stems are retained to provide structural complexity and wildlife habitat functions, or to accrue volume before removal during subsequent stand entries. The residual overstory trees and the new understory cohort will have different growth rates, and should therefore be modeled as distinct stand components. We used the redwood MASAM (multiaged stocking assessment model) to predict the growth...

Pacific madrone (Arbutus menziesii Pursh), tanoak (Lithocarpus densiflorus (Hook. & Arn.) Rehd.), and California black oak (Quercus kelloggii Newb.) are three hardwood species commonly found in the Sierra Nevada of California, an area better known for its mixed-conifer forests. Hardwood stands in this region currently are unmanaged and underutilized for commodity production. However, some landowners are now asking "How fast do these hardwoods grow," and "Will thinning increase growth and yield?" Twelve young-growth, mixed-hardwood stands on the Challenge Experimental Forest in north-central...

The Caspar Creek Experimental Watersheds were established in 1962 to study the effects of forest management on streamflow, sedimentation, and erosion in the rainfall-dominated, forested watersheds of north coastal California. Currently, 21 stream sites are gaged in the North Fork (473 ha) and South Fork (424 ha) of Caspar Creek. From 1971 to 1973, 65% of the timber volume in the South Fork was selectively cut and tractor yarded, and from 1985 to 1991, 50% of the North Fork basin was harvested, mostly as cableyarded clearcut. The South Fork logging resulted in annual suspended sediment load...