Treesearch

Mortality and diameter growth loss were severe on study plots in a thinned plantation of 9-year-old trees. California five-spined engravers killed 15 percent of the trees and a hard freeze killed 20 percent of the survivors. Mortality was higher and subsequent diameter growth was lower in trees with most of their needles freeze-killed than in trees less severely damaged in spite of occasional freeze damage at 3200 feet elevation, plantations of the hybrid can be successful if trees are closely spaced to provide for freeze mortality.

Pacific madrone, tanoak, and California black oak are the most economically promising native California hardwoods. Volume and value data indicate upward trends in growing stock levels and prices received for their products. These trends are likely to continue. They suggest research is particularly needed for: (1) seed fall and regeneration, (2) sprout growth and development, (3) stand growth and yield, and (4) species adaptation and strategy. Much new material in these categories is presented here. The ability to produce copious amounts of seed at frequent intervals is a hallmark of...

This is the authors' response to comments and criticism received following this publication: Nonturbulent dispersion processes in complex terrain

Since 1973, the Los Angeles County Forestry Division has been cooperating with the Forest Service Riverside Fire Laboratory on fire retardant plant research through yearly agreements. In 1976, the County and the PSW Experimental Station in Berkeley entered into the "Chaparral Ecology and Related Ecosystems Studies" program under which the scope of the initial agreement of fire retardant plant research was greatly expanded. In a joint meeting between personnel of the Experimental Station and the County in the summer of 1976, Project Leader Gene Conrad of the chaparral program requested that...

Increasing germination of Sophora chrysophylla seed over current levels is an important step in reforesting portions of the mamane-naio forests on the slopes of Mauna Kea, Hawaii. Three types of seedground, old pod, and new pod, were collected at four different sites and shipped to the U.S. Forest Service's Eastern Tree Seed Laboratory, Macon, Georgia, for germination tests. Seeds were subjected to three stratification regimes-cool-wet, cool-dry, and no stratification. Six seed coat treatments were applied to stratified seed: add soak, mechanical scarification, hot water soak, dry heat,...

In 1961 a feasibility study was done to determine if certain Eucalyptus species could be grown along the California North Coast for timber or ornamental purposes. Of the 207 trees, representing 31 species, planted on the Redwood Experimental Forest, only 12 trees in 5 species were recorded in the 1976 survival examination. The single most damaging factor was frost. More than 40 percent mortality was attributed to the 1972 freeze.

A sealed-edge pyramidal trap to sample total insectemergence from a segment of a small stream has been designed and tested in northeastern Oregon. The trap is approximately 10 by 10 feet at the base, and is constructed of wood, clear plastic, and galvanized screening. It is efficient and readily used, and can yield significant data on seasonal population changes and on the environmental impact of insecticides.

In a sampling of 32 logged areas in red fir forests of northern California, 58 plant species were found. Species corresponded with less than one-fifth of the 93 species reported in an earlier study of the virgin forest. Sampling of uncut areas adjacent to cuttings does not seem useful for predicting the earlier successional vegetation that will appear when the areas are logged.

Disturbance and high mortality related to human activity have apparently caused the decline of the condor population to about 50 birds. Failure to reproduce successfully is now the central problem; inadequate food supply near nest sites, lack of nest sites in new concentration areas, and pesticide accumulation in condor tissues are possible causes. Low reproductive rate hinders the recovery effort. Results of population modeling indicate that a minimum of eight nesting attempts each year is needed to maintain a population of at least 50; field data indicate that an average of only 1.8...