Treesearch

Crossing relationships were studies within and among the variable populations of Pinus muricata to test hypotheses about crossing barriers among certain populations. Crossability was assessed at the level of viable seed production following planned crosses. Populations north of Sea Ranch, Sonoma Co., California, crossed freely with parapatric but genetically distinct populations in central Sonoma Co., although some reduction in seed-set occurred in the F2 and backcrosses to F1. The distinctness of these adjacent poulations is most likely not maintained by post-pollination crossing barriers....

Allozyme differentiation at 32 loci was studied in the three Californian species of Pinus subsect. Oocarpae: P. attenuata, P. muricata, and P. radiata, and in a small sample of a Latin American species of the subsection, P. oocarpa. The Californian species were previously known to comprise highly differentiated, disjunct populations, but with uncertain phylogenetic relationships among several populations and species. All populations had clear affinities for single species. The controversial Channel Islands (Santa Cruz Island) population of P. muricata and the Mexican Island (Guadalupe and...

The lack of quality in symposia proceedings has recently been criticized by Bart and Anderson (1981). Their criticisms elicited 2 defenses of publishing symposia proceedings (Ca- pen 1982, Finch et al. 1982). These authors offered excellent suggestions for improving the quality of published proceedings: review papers before acceptance; use outside reviewers; request revisions; reject low quality papers; establish a strong organizing committee; and recognize proceedings as citable works. In this paper we build on these suggestions and offer additional guidelines for improving the quality of...

Regression equations to predict total and stem-only above-ground dry biomass for six species (Acacia melanoxylon, Albizio falcataria, Eucalyptus globulus, E. grandis, E. robusta, and E. urophylla) were developed by felling and measuring 2- to 6-year-old plantation trees on the island of Hawaii. Logarithmic transformations of the equations using diameter and height are recommended for estimating Albizia falcataria and E. grandis biomass, whereas logarithmic equations using diameter only are recommended for the other four species that have fewer sample trees collected from a single location.

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...

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 - 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...