Treesearch

First-year results of fertilization in a young ponderosa pine plantation on two contrasting soils were analyzed. Trees testing low in foliar nitrogen responded strongly to fertilization where brush had been removed, but failed to respond if brush remained. Height growth was doubled by certain treatment combinations on the less fertile Mariposa soil, but was not influenced by treatment on the more fertile Cohasset. Brush removal increased needle weight or trees on both soils. Increases in foliar biomass and nitrogen content of trees on treated plots suggest that rapid growth rates will...

Behavior of visitors on the Rainbow Trail, a Forest Service Interpretive Area in the Lake Tahoe Basin, California, was surveyed by observation and by interview. Some significant differences between trail visitors and other kinds of outdoor recreation enthusiasts were discovered. Enjoyment was high, and learning, while moderate, exceeded expectations. The Stream Profile Chamber proved to be more significant as an attraction than as an educational tool.

On large plots cleared in 1961 at three California mountain locations, different herbicide treatments were applied once, twice, or three times in consecutive years, beginning in 1962. Results were evaluated in 1965. A single spray was unsatisfactory; only the initial seedlings and weaker sprouting plants were killed, and many new seedlings became established in 1963 and 1964. Two consecutive sprays greatly reduced brush competition, but many of the vigorous sprouts survived along with numerous new seedlings. Three sprays killed almost all of the most resistant plants; only very thin brush...

Yields for high-survival, unthinned ponderosa pine (Pinus ponderosa Laws.) plantations in northern California are estimated. Stems of 367 trees in 12 plantations were analyzed to produce a growth model simulating stand yields. Diameter, basal area, and net cubic volume yields by Site Indices50 40 through 120 are tabulated for stands ranging in age between 10 and 50 years and in spacing between 6 by 6 and 12 by 12 feet. Tables also show diameter distributions by crown classes and stem volumes in cubic feet for plantation-grown ponderosa pine. These data provide both a standard with which to...

Epidemic Douglas-fir tussock moth larval populations treated with 2.0 oz, 1.0 oz, and 0.5 oz per acre of aerially applied Dimilin were reduced 99.7 percent, 92.2 percent, and 89.7 percent, respectively, at 35 days postspray. Numbers of surviving larvae per 1000 in2 were significantly different (a) at 35 days postspray, between the 2.0-oz treatment and the 1.0-oz and 0.5-oz treatments; and (b) at 28 and 35 days postspray, between the three Dimilin treatments and untreated checks. Analysis of percent unadjusted mortalities showed significant differences between the 2.0-oz treatment and the...

A set of four visual inventories are proposed. They are designed to document scenic resources for varied scales of application, from regional and general to local and specific. The Northern Great Plains is used as a case study. Scenic analysis and identification of criteria extend earlier work. The inventory is based on (1) study of previously developed landscape analysis methods and their terminology; (2) examination of high altitude imagery and topographic maps as sources of visual information; and (3) field observations in the Northern Great Plains. Criteria include visual characteristic...

The California Department of Forestry's Team Teaching Fire Prevention Program consists of small-group discussions, slides or films, and a visit by Smokey Bear to school classrooms. In a survey, teachers and principals who had experienced the program responded favorably to it. The conduct by team members also received approval. The limited criticisms of the Program centered around apparent deviations from the established format. In a separate study, students exposed to the Program scored higher in tests of their under-standing of fire prevention principles than did those who had not been...

Existing systems for estimating site index of ponderosa pine (Pinus ponderosa Laws.) do not apply well to California stands where stocking is controlled. A more suitable system has been developed using trends in natural height growth, derived from stem analysis of dominant trees in California. This site index system produces polymorphic patterns of height development to 80 years of age. Using a second system, site index can be predicted in stands where dominants have reached a breast-height age of at least 4 years but have not attained a height of 20 feet. Accuracy of estimates by this...

For 16 years Jackson State Forest, managed by the California Department of Forestry, has been the site of a comprehensive watershed experiment. This experiment, on Caspar Creek five miles south of Fort Bragg on the Mendocino coast, is a cooperative project between the California Department of Forestry and the U. S. Forest Service Pacific Southwest Forest and Range Experiment Station. The California Department of Fish and Game, the California Department of Water Resources, the California Division of Mines and Geology and Humboldt State University have been cooperators in the past

Data from two watersheds in northern California were used to develop an interpretation of the erosion hazard rating (EHR) of the Coast Forest District as amount of sedimentation. For the Caspar Creek Experimental Watershed (North Fork and South Fork), each EHR unit was estimated as equivalent to 0.0543 cubic yards per acre per year, on undisturbed forest. Experience within the District provided estimates of average excess sediment produced by logging: 17.5 cu. yd/acre for tractor yarding, and 6.3 cu. yd/acre for cable yarding. These estimates based on limited data should be supplemented by...