Treesearch

Pines on many high value recreational sites in the Western United States suffer damage and death from western dwarf mistletoe (Arceuthobium campylopodum Engelm.). Dwarf mistletoe alone, however, is not solely responsible. Other pests and environmental conditions interact with dwarf mistletoe to damage and kill trees. An integrated pest management approach can help solve dwarf mistletoe-pest related problems. The approach includes setting management goals, considering the combined effect of all other pests and environmental impacts, and using direct treatments aimed at lowering pest...

An ecological classification system has been developed for the Pacific Southwest Region of the Forest Service. As part of this classification effort, coast redwood (Sequoia sempervirens) forests of southern Monterey County in the Los Padres National Forest were classified into six ecological types using vegetation, soils and geomorphology taken from 115, 0.1-acre plots. Four types occur between 100 and 800 ft elevation. The coast redwood/bracken fern-chain fern//streamsides ecological type occupies the narrow flood plains, streambanks and scattered alluvial terraces of large perennial...

The need for protection from uncontrolled fire in California was identified by Abbott Kinney, Chairman of the State Board of Forestry, more than 75 years before the construction of the Riverside Forest Fire Laboratory. With the organization of the USDA Forest Service the need for an effective fire protection organization became apparent. In response, a somewhat fragmented research program got under way in the 19 10's. Although the research was successful in reducing fire damage undermost conditions, severe fire years still made it clear that a strong cohesive fire research effort, headquart...

Measures of performance in wild ungulates can include characteristics indicative of condition and health such as body weights, fat reserves, blood values, reproductive rates, and parasite loads. Performance may also be inferred from habitat-related factors, such as diet and nutritional intake. However, these parameters interact with population density to form a homeostatic system that tends towards equilibrium over time, subject to other extrinsic variables. Therefore, performance in ungulates should be judged with reference to a specific population density. Estimates of population density...

The San Dimas Experimental Forest serves as a field laboratory for studies of chaparral and related ecosystems, and has been recognized by national and international organizations. It covers 6,945 ha (17,153 acres) in the foothills of the San Gabriel Mountains northeast of Los Angeles, and has a typical Mediterranean-type climate. The Forest encompasses the San Dimas and Big Dalton watersheds, which have vegetation typical of southern California, are separated by deep canyons from the rest of the San Gabriel Mountains, have small tributaries suitable for study, and are harnessed by flood...

In recent years, serious die-back of forest trees has been reported in western Europe and eastern North America. One presumed cause of the forest decline is air pollution and acid deposition. Concern has been expressed that adverse hydrologic responses might occur in forested watersheds as the result of reduced evapotranspiration and increased discharge. According to one hypothesis, elevated soil-water storage might increase peak flows and cause stream channel damage or downstream flooding. This hypothesis is explored by reviewing the literature, recomputing published data, and simulating...

Abstract - Storm yields of water and sediment are being measured as part of a study of the effects of roading, logging, and burning in a second-growth redwood forest in northern California. Two primary basins, each about 500 ha, and 13 sub-basins in one of them are measured for sediment flux and the presence and magnitude of sediment-based ""cumulative effects"". Study objectives require a more sophisticated sediment sampling design than typically used in watershed experiments. Sediment is sampled and estimated by using PSALT - a probability-based method for sampling that enhances data...

Abstract - Rating curves are widely used for directly assessing changes in the suspended sediment delivery process and indirectly for estimating total yields. Four sampling methods were simulated-over a 31-day record of suspended sediment from the North Fork of the Mad River near Korbel, California. The position and size of the four groups of plotted slope/intercept pairs indicated differences in bias and variance among the methods. Estimates of total yield for the 31-day period and for storms of three sizes were also biased according to sampling method. A standard bias-correcting technique...

The Hammond's (Empidonax hammondii) and Western (E. difficilis) flycatchers are sympatric within portions of their breeding ranges in north- western California. Westerns are common in a variety of habitats (Bent 1942:247, Johnson 1980:11-23); Hammond's are more abundant at higher elevations (Bent 1942:226, Johnson 1963:140-143). Only one ma- jor study of each species' breeding biology has been reported; both looked at the species in places where they do not occur together. Davis et al. (1963) studied the breeding biology of Westerns in a hardwood-dominated forest in northern Monterey...