Treesearch

Thinning ponderosa and Jeffrey pine pole stands (6 to 8 inches d.b.h.) on Meyer Site Classes IV and V land (site index 65 to 80) stimulates growth in diameter and height. This was concluded from data on 12 thinned plots scattered over northeastern California, in natural stands and in a plantation. Basal areas immediately after thinning ranged from 13 to 149 square feet per acre. Stands had many dissimilarities before thinning. Nevertheless, results allow the conclusion that thinning to about 80 square feet of basal area per acre will bring such stands to merchantable size as rapidly as...

Abstract - This paper summarizes our current understanding of the effects of timber harvesting on erosion. Rates of erosion on mountain watersheds vary widely but the relative importance of different types of erosion and the consequences of disturbances remain fairly consistent. Therefore these conclusions seem to be valid for most circumstances: Most of man's activities will increase erosion to some extent in forested watersheds; erosion rarely occurs uniformly; sediment production declines rapidly following disturbance; landslides and creep are the chief forms of natural erosion in...

An analytical procedure to help management decision-making in planning government research is described. The objectives, activities, and restrictions of a government research organization are modeled in a consistent analytical framework. Theory and methodology is drawn from economics and mathe-matical programing. The major analytical aspects distinguishing research from other forms of economic activities are examined. The characteristics and potential uses of a management information system are outlined.

A set of computer programs compiled for the information processing requirements of a model for evaluating research proposals are described. The programs serve to assemble and store information, periodically update it, and convert it to a form usable for decision-making. Guides for collecting and coding data are explained. The data-processing options available and instructions on operation of the software are outlined.

Effects of four light intensities on germination, survival, and early growth of Douglas-fir (Pseudotsuga menziesii) were studied on south-facing cutblocks in northwestern California. Tested were four shade intensities: 0, 25, 50, and 75 percent. On seeded spots, 50 percent shade resulted in greatest germination and survival, being significantly better than either no shade or 25 percent shade, but not better than 75 percent-shade. Shade did not significantly improve the survival of planted trees (either 1-0 or 2-0 age class), but growth was generally best on plots with least shade. Good...

A trial of rest-rotation grazing was started in 1954 on the Harvey Valley allotment of the Lassen National Forest, northern California. This paper evaluates progress observed to 1966. Ecologically the program is considered sound. And after only a decade, the allotment was in better condition than allotments grazed season-long. Cattle weight gains were acceptable, and as good as could be expected from the surrounding area. In terms of short-term monetary cost in relation to returns, rest-rotation grazing cost the Forest Service 28 percent and the livestock permittee 9 percent more than did...

Permits were first needed for visits to wilderness areas in California during summer 1971. A computerized system for analyzing these permits and summarizing information from them has been developed. It produces four types of summary tables: point-of-origin of visitors; daily variation in total number of persons present; variations in group size; and variations in length of stay. The Wilderness Information system was tested by analyzing 23,936 permits issued for six California wilderness areas in summer 1971.

Xylem resin of Pinaceae is closely linked with their resistance and suseptibility to tree-killing bark beetles. This review of the literature on attacking adults suggests that all three resistance mechanisms proposed by Painter -- preference, antibiosis, and tolerance -- are active in this relationship: preference by attraction, repellency, and synergism; antibiosis by both chemical and physical properties; tolerance by healing and secondary resinosis.

Balsam fir seedlings were grown under uniform conditions from seed collected along an elevational gradient in the White Mountains of New Hampshire. Photosynthetic temperature optimum of the seedlings decreased with increasing elevation of the seed source. The change in temperature optimum with elevation was similar to the adiabatic lapse rate, suggesting a precise adaptation to temperature through natural selection.