Treesearch

White fir seeds collected from 43 sources were sown at the Institute of Forest Genetics, Placerville, Calif. in 1963. Observations made 3 years later showed that seedlings from northern sources sustained more winter injury than did southern origin seedlings. Seedlings from low elevations were less severely damaged than seedlings from higher elevations in the same general locality.

The results of hybridizing the western pine species by the Institute of Forest Genetics are described and discussed. It has been found that the hard, (yellow) pines can generally be crossed successfully only with similar species native to the same part of the world. In contrast, the soft (white) pines of the Western Hemisphere have been crossed successfully with soft pines of the Eastern Hemisphere. The hybrids produced by the Institute have been found to have value in both the field of forestry and in improving mans environment.

Soils that resist wetting are a widespread phenomenon on chaparral areas of southern California watersheds. On burned watersheds, non-wettable soils markedly reduce moisture movement during both evaporation and infiltration. The reduced infiltration rate probably contributes significantly to the high debris production from the watersheds. Factors involved in the formation of non-wet-table soils include vegetation and soil temperatures during fire. Wetting agents applied to burned areas apparently help retard debris movement and enhance vegetation establishment.

Twenty-nine soil-vegetation plots were studied in a broad transect across the southern Cascade Range. Variations in soil moisture patterns during the growing season and in soil moisture tension values are discussed. Plot soil moisture values for 40- and 80-cm. depths in August and September are integrated into a soil drought index. Vegetation patterns are described in relationto this index. Use of data on species presence for a vegetation drought index is explored.

Three prescribed burns, made in 1959-62, in the interior ponderosa pine type of northeastern California are described in terms of meteorological factors, fire behavior, and effects of burning. Results were generally unsatisfactory. Factors that limit the usefulness of prescribed burning for reducing fuel hazard or for thinning in young-growth stands include stand structure, weather patterns, and costs.

An estimated 44,300 new housing units will be required in Hawaii during the period 1965-70. Single family houses are expected to comprise 20,000 to 26,000 of these units. Housing demand is assumed to be related to population growth, age of existing housing units, and disposable income of potential home buyers. The factors affecting house construction are described.

The Department of Fish and Game assisted in an interagency study on Caspar Creek, a small coastal stream in Mendocino County. This study included the effects of logging on the stream and its population of silver salmon (Oncorhynchus kisutch) and steelhead trout (Salmo gairdnerii).

Describes how to use an improved and greatly expanded version of an earlier computer program (1964) that converts dendrometer measurements of 3P-sample trees to population values in terms of whatever units user desires. Many new options are available, including that of obtaining a product-yield and appraisal report based on regression coefficients supplied by user. Improved techniques for extrapolation may be employed to estimate unseen length and upper bark thickness.

Abstract - Moisture measurements were made in three media--paraffin, water, saturated sand--with four neutron moisture meters, each containing 226-radium-beryllium, 227-actinium-beryllium, 239-plutonium-beryllium, or 241-americium-beryllium neutron sources. Variability in surface detection by the different sources may be due to differences in neutron sources, in length of source, or both

A number of radioisotopes have recently become commercially available as alternatives to radium-225 in moisture gauging devices using alpha-neutron sources for determining soil moisture, for well logging, and for other industrial applications in which hydrogenous materials are measured.