Treesearch

Smoked aluminum track stations are a useful technique for studying patterns of abundance and distribution of northern flying squirrel (Glaucomys sabrinus). They are easily transported to remote field sites, allow permanent preservation of tracks, and yield frequency-of-occurrence information. A study in Douglas-fir (Pseseudotsuga menziesii) forests of northwestern California illustrates the use ofthe track stations, methods of data analysis, and habitat associations of the northern flying squirrel.

Overstory removal can offer economic and esthetic advantages over clearcutting and regeneration, but projecting success is difficult. Twenty-nine units on nine operational overstory removal cuts in northern California were studied to determine what factors are related to satisfactory or unsatisfactory stocking after harvest. Stocking determinations were based on number of trees meeting minimum crop tree standards. Although all of the postharvest stands contained adequate numbers of trees, only about half passed minimal stocking standards based on number of trees meeting crop tree criteria....

Abstract - SALT (Selection At List Time) is a variable probability sampling scheme that provides unbiased estimates of suspended sediment yield and its variance. SALT performs better than standard schemes which are estimate variance. Sampling probabilities are based on a sediment rating function which promotes greater sampling intensity during periods of high sediment yield. When preparing to monitor using SALT, the quality of the existing suspended sediment rating data is an important consideration. SALT variance, based on an intensive data set from a river in northwestern California,...

Some of the most productive forests in the Western United States grow on marginally stable mountainous slopes, where disturbance increases the likelihood of erosion. Much of the public's concern about, and, consequently, most of the research on, erosion from these forested areas is related more to the degradation of stream resources by eroded material than to the loss of soil and nutrients from hillslopes. Erosion from these upper watersheds is a composite of surface, channel, and mass erosion processes. The relative importance of each process is determined by interactions among climate,...

Abstract - The effects of woody debris on anadromous salmonid habitat in eight streams on Prince of Wales Island, southeast Alaska, were investigated by comparing low-gradient (1-9%) first- or second-order streams flowing through either spruce-hemlock forests or 6-10-year-old clearcuts, and by observing changes after debris was selectively removed from clear-cut reaches. Woody debris decreased the rate of shallowing as discharge decreased, thus helping to preserve living space for fish during critical low-flow periods. Debris dams were more frequent in clear-cut streams (14.9/100 m), which...

To determine the effects of different burning intervals on soil N status in substands of sapling-, pole-, and sawtimber-sized ponderosa pine (Pinus ponderosa Laws.) we sampled plots burned at 1-, 2-, and 4-yr intervals by three strata at two depths (0-5 and 5-15 cm). Generally, NH4 +; and NO3 - concentrations were higher on plots repeatedly burned than on unburned controls. However, plots not reburned for 4 to 5 yr had concentrations similar to controls. No significant difference in total (organically bound) N was found among treatments. We conclude that frequent periodic burning can be...

Gene conservation has three facets: (1) the maintenance of diversity in production plantations to buffer against vulnerability to pests and climatic extremes; (2) the preservation of genes for their future value in breeding; (3) the protection of species to promote ecosystem stability. Maintaining diversity as a hedge against damaging agents is a simple strategy in theory. In practice, economic forces tend to favor genetic monocultures to maximize short-term gain.

The protection of anadromous fish habitat is an important water quslity concern in the Pacific Northwest. Sediment from logging-related debris avalanches can cause habitat degradation. Research on conditions associated with the sites where debris avalanches originate has resulted in a risk assessment methodology based on linear discriminant analysis. The probability of causing a debris avalanche by clearcutting can be coupled with an appraisal of the resulting costs and benefits to estimate the risk threshold which maximizes the forest manager's value system.

Researchers at Blodgett Forest Research Station, University of California, are studying giant sequoia (Sequoiadendron giganteum [Lindl.] Buchholz) growth under both even-age and selection management in relationship to the presence of several shrub species and five native conifers. The sequoias are also being studied under several types of site preparation, vegetation control techniques, and stand densities. Seven management units are described. In virtually all situations, early (first 18 years) height and diameter growth patterns of sequoia equal or exceed those of native conifers.