Treesearch

Historical and technical background is provided about ozone air pollution effects on ponderosa (Pinus ponderosa Dougl. ex Laws) and Jeffrey (P. jeffreyi Grev. and Balf.) pines in forests of the western United States. The principal aim is to document the development of field survey methods to be applied to assessment of chronic ozone injury by government agencies responsible for management of forest and air resources, primarily in the Sierra Nevada and mountains of southern California. Detailed procedures are supplied for the selection of sample plots, collection of plot and tree data,...

Use by bats of basal hollows in old-growth redwoods was indexed using the weight of guano collected on water-permeable screens (guano traps) installed inside the trees. Twenty-six trees were systematically selected from a stand that flanks both sides of an interstate highway in Del Norte Co., California. Traps were checked for guano once a month for 18 months. The quantity of guano collected each month and that every tree was used suggests that the trees served either as day roosts by small numbers of bats or as temporary night roosts. Although bats could not be identified on the basis of...

Microhabitat analyses often use discriminant function analysis (DFA) to compare vegetation structures or environmental conditions between sites classified by a study animal's presence or absence. These presence/absence studies make questionable assumptions about the habitat value of the comparison sites and the microhabitat data often violate the DFA's assumptions of an equal covariance structure and multivariate normality. An alternative is to generate an ordinal measure of site-use intensity from radiotelemetry locations. This measure is derived from the percentage of total telemetry...

I n forests, the canopy is the locale of critical ecosystem processes such as photosynthesis and evapotranspiration. and it provides essential habitat for a highly diverse array of animals, plants, and other organisms. Despite its importance, the structure of the canopy as a whole has had little quantitative study because limited access makes quantification difficult and integration of detailed measures of many individual tree crowns is necessary. A model is presented for simulating the crown architecture of individual trees in the Pacific Northwest to analyze their collective influence on...

The increasing use of harvest techniques other than clearcutting in forests west of the Cascade mountains has created an urgent need to understand the effects of these practices on ecosystem species composition and structure. One common alternative, "green tree retention" (GTR), leaves some live trees on a harvest site to more closely mimic a moderate-intensity fire or wind disturbance. We examined the response of understory plant diversity and basal area increment of retained overstory trees after sixteen months and six years, respectively, in GTR cuts. Understory species cover was...

Atmospheric concentrations and deposition of the major nitrogenous (N) compounds and their biological effects in California forests are reviewed. Climatic characteristics of California are summarized in light of their effects on pollutant accumulation and transport. Over large areas of the state dry deposition is of greater magnitude than wet deposition due to the arid climate. However, fog deposition can also be significant in areas where seasonal fogs and N pollution sources coincide. The dominance of dry deposition is magnified in airsheds with frequent temperature inversions such as...

Tree volume equations for tanoak (Lithocarpus densiflorus) were developed for seven stands throughout its natural range and compared by a volume prediction and a parameter difference method. The objective was to test if volume estimates from a species growing in a local, relatively uniform habitat could be applied more widely. Results indicated that they could not. Diameter slope coefficients and intercepts differed at the 5% probability level. Tree height slope coefficients did not differ, but when all slope coefficients (dbh and height) were combined, a significant difference was...

Abstract - Flow-stratified sampling is a new method for sampling water quality constituents such as suspended sediment to estimate loads. As with selection-at-list-time (SALT) and time-stratified sampling, flow-stratified sampling is a statistical method requiring random sampling, and yielding unbiased estimates of load and variance. It can be used to estimate event yields or to estimate mean concentrations in flow classes for detecting change over time or differences from water quality standards. Flow-stratified sampling is described and its variance compared with those of SALT and...

The California Department of Conservation, Division of Mines and Geology (DMG) is submitting this report and accompanying maps to the California Department of Forestry and Fire Protection (CDF) to fulfill Interagency Agreement number 8CA38400, Pilot Monitoring Program -- Geologic Input for the Hillslope Component. Under this agreement, DMG has assisted CDF in the development of hillslope monitoring techniques needed to evaluate the effectiveness of the Forest Practice Rules in protecting water quality. The major component of DMG’s work involved defining the physical characteristics of the...