Treesearch

Abstract - The precision of timing devices in modern electronic data loggers makes it possible to study the routing of water through small drainage basins having rapid responses to hydrologic impulses. Storm hyetographs were measured using digital tipping bucket rain gauges and their routing was observed at headwater piezometers located mid-slope, above a swale, and near the swale. Downslope, flow was recorded from naturally occurring soil pipes draining the 0.8-ha swale. Progressing downstream from the swale, streamflow was measured at stations gauging nested basins of 16, 52, 156, 217,...

Using a previously treated basin as a control in subsequent paired watershed studies requires the control to be stable. Basin stability can be assessed in many ways, some of which are investigated for the South Fork of Caspar Creek in northern California. This basin is recovering from logging and road building in the early 1970s. Three storm-based discharge characteristics (peak discharge, quick flow, and total storm flow), daily flows, and concentration of suspended sediment were studied to see if the South Fork can be used as a control in a second experiment. Mean sediment concentration...

Streamflow data for a 21-year period were analyzed to determine the effects of selective tractor harvesting of second-growth Douglas fir and redwood forest on the volume, timing, and duration of low flows and annual water yield in northwestern California. The flow response to logging was highly variable. Some of this variability was correlated with antecedent precipitation conditions. Statistically significant increases in streamflow were detected for both the annual period and the low-flow season. Relative increases in water yield were greater for the summer low-flow period than for...

A population of 638 timber harvest areas in northwestern California was sampled for data related to the occurrence of critical amounts of erosion (>153 m3 within 0.81 ha). Separate analyses were done for forest roads and logged areas. Linear discriminant functions were computed in each analysis to contrast site conditions at critical plots with randomly selected controls. Bootstrapping was used extensively in the development and testing of the equations, in estimating prediction bias, and in placing confidence limits around parameters and posterior probabilities. The resulting three-variabl...

Caspar Creek experimental watersheds are located on the Jackson Demonstration State Forest. Sponsors are the Pacific Southwest Research Station (PSW), USDA Forest Service, and the California Department of Forestry and Fire Protection (CDF). Both organizations have been working cooperatively since 1962

Stream temperature measurements have been collected in the Caspar Creek drainage on Jackson Demonstration State Forest periodically over the past 25 years. Review of this data and other recently collected data from western Mendocino County illustrates much about the temperature regimes of small coastal drainages, and how they are impacted by timber harvesting. This article gives a synopsis of these studies and summarizes reasons for concern. Additionally, it presents a model currently in use by the U.S. Forest Service to predict changes in maximum summer temperatures resulting from canopy...

A primary goal for JDSF is to carry out research on the various aspects of forestry in the redwood region. One avenue to do this has been to encourage university forestry departments to do experimental projects here. Since 1980, funding for many researchers has been provided through CDF's Forest Resource Improvement Fund (FRIF). Each year, money is made available to various State Forests for Research projects which the Manager feel have the highest priorities. Graduate students have often been the actual principal field investigators and many theses have been produced.

Studies of the foraging behaviors of birds have been largely descriptive and comparative. One might then expect studies with similar objectives to have similar study designs but that is not the case. Papers in this symposium that focused specifically on study design contain a diversity of biological perspectives. Similarly, there is no accord among statisticians on experimental design and data analysis of multivariable systems. Further, biological and statistical considerations in study design are not always in agreement.