Treesearch

Douglas-fir seedlings on the Arcata Resource Area, Bureau of Land Management, U.S. Department of the Interior, in central coastal California, were released by chain sawing and grubbing competing vegetation around them at different frequencies (0, 2, and 3 grubbings) over a 5-year period. After 5 years, average Douglas-fir stem diameter (measured at 12 inches above mean groundline) of seedlings grubbed at ages 1,2, and 5 was 0.91 inches, and of seedlings grubbed after the first and fifth growing season was 0.95 inches. Both were significantly larger than counterparts in the control (0.57...

These proceedings summarize the results of a blending of public perceptions, management, and research presented at a symposium on Giant Sequoias (Sequoiadendron giganteum), held in Visalia, California. Twenty-eight papers are included, focusing on six major topics: public values and perceptions, natural perspectives, disturbance environments, grove development, management strat-egies, and views from agency leadership. These papers summarize the state of knowledge and perceptions of this magnificent species and their place in ecosystems and society.

We tested the pyrethroid insecticide esfenvalerate in single, double, and triple applications for control of insects affecting seed production of blister rust-resistant western white pine, Pinus monticola Douglas. All treatments increased the proportion of normal seed produced and reduced the proportion of seed damaged by the western conifer seed bug, Leptoglossus occidentalis Heidemann. Only the triple application reduced the proportion of cones killed by the pine cone beetle, Conophthorus ponderosae Hopkins. Other seed-damaging insect species [seed chalcids, Megastigmus sp.; the fir...

For the past two decades, researchers from the Pacific Southwest Station, in cooperation with the California Department of Forestry (CDF), have been studying the effects of logging on the integrity of northern California watersheds. Their findings have greatly illuminated the extent and nature of the hydrologic impact, erosion, and stream sedimentation for a northern California basin undergoing a "typical" logging operation.

Abstract - This annual study has been conducted, since 1987, on two coastal streams, in order to observe the different trend patterns of juvenile out migrations for coho salmon and steelhead-trout, figure 1. Analysis of the 1993 trapping season indicates, at Little River, a decrease of steelhead-trout yearlings but an increase in coho ""y+"". Coho and trout yearlings, at Caspar Creek, simultaneously tapered in late May and were similar in magnitude, appendix 1 and graph 2. Coho ""y+"" smolts, at both estuaries, migrated from late April till late May. Steelhead-trout ""y+"" smolts were...

The objectives of this study were to determine winter food sources, availability, and preferences for coho salmon (Oncorhynchus kisutch) and steelhead (Oncorhynchus mykiss) in Pudding Creek, California. The majority of research on overwintering strategies of salmonids on the West Coast has been done in cooler, northern climates studying primarily the role of habitat and secondarily, if at all, the role of food availability and diet. Refuge from high flows, high sediment loads, and freezing temperatures can be essential for overwintering fish (Mundie and Traber 1983, Dolloff 1987, Hartman...

Time-stratified sampling of sediment for estimating suspended load is introduced and compared to selection at list time (SALT) sampling. Both methods provide unbiased estimates of load and variance. The magnitude of the variance of the two methods is compared using five storm populations of suspended sediment flux derived from turbidity data. Under like conditions, the SALT coefficient of variation was 1.4-7.7 times that of time-stratified sampling. Time-stratified sampling performs well if the range of sediment flux in each stratum is small. This requirement can be met by using small...

In 1977 extensive data were collected to calibrate six Helley-Smith bed load samplers with four sediment particle sizes in a flume at the St. Anthony Falls Hydraulic Laboratory at the University of Minnesota. Because sampler data cannot be collected at the same time and place as ""true"" trap measurements, the ""probability-matching method"" was used to derive surrogate pairs for calibration analysis. The Method is invalid since it implicitly assumes that sampler and trap data have no sampling or measurement errors, it gives biased and highly variable results, and it does not contain...

USDA Forest Service research scientists have recently accelerated research on the development of bark beetle management systems. This accelerated program was developed in response to the strong public reaction to widespread tree mortality and other forest health problems in several western states. To meet the public's concerns, Congress appropriated funds to initiate a Western Bark Beetle Research and Development program. The program was carried out by research scientists and cooperators in three USDA Forest Service Research Stations: Pacific Southwest, Pacific Northwest, and Intermountain...