Treesearch

The strong band of low-level winds that affected the severity of the San Mateo and Walker Fires in southern California on August 1969 was analyzed and studied. Mechanisms that could have caused or contributed to these winds and similar wind situations were evaluated and are discussed. Results show that the winds in this case were probably a product of several mechanisms in combination.

Mail questionnaires and follow-up interviews were used to determine preferences among three types of floor foundations: concrete slab, wood crawl-space, and a new design that combines a low-profile wood floor with underfloor plenum. Crawl-space construction was preferred in the Sacramento and Oakland-Martinez markets; concrete slab was preferred in the Los Angeles, San Diego, and Phoenix markets. Preference was about evenly divided in the Fresno market. More than 60 percent of the respondents would consider the new underfloor plenum design.

Tree quality and rates of growth and survival were higher in 5- to 8-year-old Australian toon (Toona australis) plantations on sites with deep soils, good drainage, and as or broken pahoehoe rock than in plantations on sites with poor drainage or unbroken pahoehoe rock. Stocking averaged 236 trees per acre. Spacing in initial plants should be about 6 by 7 feet to 8 by 9 feet–depending on expected survival. And during the first few months, weeding and replanting should be done.

Relation of population density to certain stand conditions and damage indicators was analyzed in four drainages on the Bitterroot National Forest of Montana. Western spruce budworm (Choristoneura occidentalis Freeman) populations were strongly related to plot basal area, tree species, and tree crown levels, and also to current and past levels of tree defoliation. Relatively open stands of thrifty trees are recommended, with logging of true fir and Douglas-fir to favor nonhost trees, to reduce vulnerability to excessive budworm damage.

Mail questionnaires and follow-up interviews were used to determine preferences among three types of floor foundations: concrete slab, wood crawl-space, and a new design that combines a low-profile wood floor with underfloor plenum. More respondents from northern markets preferred the crawl-space floor than from the southern markets. Factors most often cited as influencing preference were protection from termites, expected ease of reselling a house, and previous knowledge of or experience with a type of floor construction.

Steady state gene frequencies around a pocket of differential fitness have been formulated by Hanson (1966) in a generalization of the work of Haldane (1948). A pocket of differential fitness would result in a pocket-of-variability, assuming that the radius of the area of contrasting fitness was large in relation to the vagility of the organism. Conversely, the absence of a pocket-of-variability is predicted whenever dispersal is broad relative to the size of the pocket of differential fitness. Around the pocket, a cline would be established through the interaction of migration and...

Infiltration continues to occupy the attention of soil physicists and engineers. A theoretical and experimental analysis of the effect of surface sealing on infiltration by Edwards and Larson [1969] showed that raindrops reduced the infiltration rate by as much as 50% for a two-hour period of infiltration. The effect of raindrops on the surface infiltration rate of soils has been investigated by Seginer and Morin [1970] who used an infiltration model based on the Horton equation.

The movement of 14-C from the old needles to the roots, and later to the new needles, was measured in 2-year-old ponderosa pine seedlings. The seedlings were in one of three growth stages at the time of the feeding of 14-CO-2: 9 days before spring bud break with no root activity; 7 days before spring bud break with high root activity; and 7 days after spring bud break with moderate root activity. The form of the curves of count rate plotted against time are similar for a given plant part

Yields of juvenile steelhead rainbow trout Salmo gairdnerii gairdnerii) and silver salmon (Oncorhynchus kisutch) emigrants were compared in South Fork Caspar Creek, a small coastal stream in Mendocino County, California, before and after construction of a logging road along the stream in the summer of 1967. Numbers, lengths, and age class structures were compared.

The Caspar Creek Watershed Study was initiated in 1960 to study large differences between conditions of stream flow and sedimentation, fish life and fish habitat between paired watersheds, one of which will be carefully logged while the other is left undisturbed as a control. This study will not compare differences in types of logging practices.