Treesearch

An exploratory experiment, designed to determine the effect of color on recall in fire prevention signing, was conducted on the San Bernardino National Forest. Background color of usual black on light yellow fire prevention signing, was changed to bright, high intensity orange. The change may have affected impact, but did not improve recall. Frequency of exposure to fire prevention signs influenced the number of signs reported observed.

Presents guides to determine the number of seeds to sow per spot and the number of spots required per acre to obtain acceptable stocking. Based on theoretical probabilities, these guides were found to be reasonably close to actual field results When the probability-of-success was at least 55 percent. To compensate for lower actual stocking, increase the number of spots per acre rather than sow more seeds per spot.

Statistical models were devised for estimating both daily and seasonal attendance (and corresponding precision of estimates) through correlation-regression and ratio analyses. Total daily attendance for a test set of 23 campgrounds could be estimated from attendance measured in only one of them. The chances were that estimates would be within 10 percent of true attendance, 2 out of 3 times. Specific procedures for field use will rest on each user's requirements for precision and cost.

Moisture content in Douglas-fir cull logs and boles of felled tanoaks was sampled periodically at 2-inch intervals to a depth of 6 inches from October 1960-0ctober 1961. The study area had been clear cut in 1958 and the hardwoods felled in 1959. Analysis of the data showed that the moisture level in tanoak stems decreased at an increasing rate from a 6-inch depth to the surface, whereas Douglas-fir moisture content increased at an increasing rate in this same direction.

A survey of the output of primary forest products in Hawaii in 1963 showed that the total value was $230,000. Compared with 1960, the total quantity of material declined but total value increased.

Dwarfmistletoes (Arceuthobium spp. ) parasitize and damage most native conifers of California. The study of chemical control for dwarfmistletoe on pines and true firs was resumed in 1959. Over the past 5 years, 246 tests on 2, 516 trees of five species have been started, Many phenoxy herbicides and some other materials were applied as sprays in fuel oil and water carriers. An isooctyl ester of 2, 4, 5-trichlorophenoxy butyric acid is the most promising herbicide so far tested for direct spray treatment of dwarfmistletoe on pines.

Parallel series of exploratory experiments with antifungal antibiotics and conventional chemical fungicides for control of blister rust on sugar pine were started in northern California in 1959. Several fungicides, both antibiotic and conventional, appear slightly systemic, but all tested materials are more effective when sprayed directly on infected tissues. Conventional fungicides appear as effective as antibiotics for direct control of blister rust. Large differences in effectiveness appear due to concentration of fungicide and to season of application.

A study of air-drying 4/4 Eucalyptus robusta lumber in Hilo, Hawaii showed that during typical summer weather it can be dried to below 20 percent moisture content in 2-1/2 months. Grade reduction in 36 percent of the lumber was caused by end splits, insect damage, warp, and surface checking.

Presents rating curves applicable to small and large flume installations in which approach velocity permits a hydraulic control to exist. The accuracy to be expected from these curves is tabulated and plotted against field observations. The rating curves should be considered only indicative of the actual flow rates when applied to runoff containing appreciable debris quantities. Criteria are given for modifying field installations, without a hydraulic control at the flume inlet.

Stream pollution has not resulted from removing and chemically spraying vegetation at the bottom of Monroe Canyon on the San Dimas Experimental Forest. The riparian zone and intermediate slopes were handsprayed several times with a mixture of 2,4-D and 2,4,5-T herbicide. In another study, brush on side slopes was cut and sprayed. Soil samples taken the first month after treatment showed no traces of herbicides.