Treesearch

In California, the Lake Albacutya provenance of river red gum was clearly superior in volume growth to 22 other provenances collected throughout the range of the species in Australia. It had at least 2.5 times the volume of the plantation mean at 5.5 years, consistent with its performance in other countries with Mediterranean climates like California's. Other provenances from southeastern Australia, particularly those in the Murray River basin, also performed well.

Abstract - In 1972, declining coho salmon production and visible forestry impacts on coho habitats prompted the initiation of an ongoing fisheries research project in the Clearwater River basin of the Olympic Peninsula. Heavy fishery catches have resulted in a general under-seeding of the basin, as demonstrated by stocking experiments and inventories of potential habitat. Because of the resulting lack of a reservoir of surplus juveniles, the number of smolts produced is more sensitive to natural and forestry-related impacts.

Site index curves for young-growth California white fir were developed by using stem analysis data from 77 dominant and codominant trees growing in mixed-coniferstands on the western slopes of the Sierra Nevada. Site index reference age is 50 years at breast height. A family of 11 curves is presented for site index estimation. For more precise estimates, the site index estimating equation can be solved by using appropriate values of total tree height and breast-height age.

Abstract: Along-term thinning study was established in ten stands of coast live oak (Quercus agrifolia N in the Central Coast of California. Information about diameter, basal area, and volume growth and yield is being obtained from unthinned control plots and from plots thinned to 50 and 100 square feet of basal area per acre. Descriptive information was also collected about the overstory, understory, and the site. Remeasurement at 5-year intervals will provide valuable data about the effects of thinning in coast live oak stands.

Positive correlations between measures of "fitness" and the number of electrophoretic loci for which an individual is heterozygous have been observed in many species. Two major hypotheses have been proposed to explain this phenomenon: inbreeding depression and overdominance. Until recently, there has been no way to distinguish between these hypotheses. The overdominance model devised by Smouse (1986) is used here in a reanalysis of Ledig et al.'s (1983) study of heterozygosity and growth rate in eight populations of pitch pine and is contrasted with an inbreeding-depression analysis. Ledig...

A test of open-pollinated pitch pine families from 17 different locations on the Atlantic Coastal Plain was evaluated at 12 years of age. Genetic variation for growth was almost totally on the provenance level and was detectable among families within provenances in only a few cases. Mean volume decreased with latitude and also with distance of the seed origin from the test site. Provenances with the largest mean volume per tree came from locations 5.3 and 24.8 km distant from the test site and those with the smallest, from 349 and 388 km distant. The frequency of trees with serotinous...

Fire management simulation models are used to predict the impact of changes in the fire management program on fire outcomes. As with all models, the goal is to abstract reality without seriously distorting relationships between variables of interest. One important variable of fire organization performance is the length of time it takes to get suppression units to the fire. Because the location of the fires cannot be predicted and because suppression units are not always available at a particular base location, the types of units sent and their arrival times vary This aspect of fire...

Western dwarf mistletoe (Arceuthobium campylopodum) is a damaging parasite of Jeffrey pines (Pinus jeffreyi) in southern California. Infected branches that develop into brooms are believed to reduce tlee vigor and increase mortality. Brooms were pruned from Jeffrey pines with varying levels of dwarf mistletoe infection and live crown. Many of the trees showed an increase in crown vigor when compared with unpruned trees after 5 years. Mortality was not reduced by pruning brooms, except during years of below-normal precipitation. Of the trees that died, most had little live crown, heavy...

Abstract - Using a low flow season defined as a function of antecedent precipitation, streamflow data for a 21 year period was analyzed to determine the effects of selective tractor harvesting of second-growth Douglas-fir and redwood forest on the volume, timing, and duration of low flows and annual water yield. Significant increases in streamflow were detected for both the annual period and the low flow season. Maximum increases were realized the year following the completion. of logging. Greater relative increases were witnessed for the summer low flow period, however these increases...