Treesearch

Screens made of hardware cloth are commonly used to protect seed-spots in forest plantations from the depredations of birds and rodents. It is important to know whether or not the screens influence germination and survival of seedlings in addition to furnishing protection against animals.

The logical procedure for the improvement of all wild stock of any kind, whether plant or animal, is practically the same: segregation of varieties, races, and strains of the wild population; the evaluation of the characteristics of each group; the selection of the best individuals from each of the best strains; utilization of these in breeding and selection; and finally the production of new types(5).

Various sampling strategies are evaluated for efficiency in an interior ponderosa pine forest. In a 5760 acre tract, efficiency was gained by stratifying into quarter acre blocks and sampling randomly from within. A systematic cruise was found to be superior for volume estimation.

Experimental forests, watersheds, and ranges are the field laboratories in the research structure of the Forest Service. The California Forest and Range Experiment Station maintains four experimental forests representing the more important timber types in the Pine Region. The Blacks Mountain Experimental Forest represents the ponderosa pine type of California's northeastern plateau, commonly called "east slope" pine. The type occupies approximately 3,700,000 acres of which about 2,700,000 acres are virgin timber. Lumber is the principal source of income from land in this type. A severe...

Not long ago the object of forestry was pretty generally considered to be the growing of timber, and forest planting was concerned almost exclusively with the planting of lumber producing trees. The text-books, it is true, have given increasing attention to the part played by ground-cover vegetation in forest ecology, but these discussions have rarely suggested the actual cultivation of such plants. Gradually, and with rapid acceleration in recent years, the concept of forestry has broadened to keep pace with a growing recognition of the importance of other uses of the forest, such as...

The Teakettle Creek Experimental Watersheds lie for the most part on quartzites of probable Triassic age. However one of the triplicate drainages has a considerable acreage developed on weathered granodiorite. Topography is relatively uniform and lends itself to triplicate watershed studies. Locations for dams are suitable if certain engineering precautions are taken. So far as observed botanic and soil conditions also lend themselves to experimental watershed studies.

Preliminary investigations in the detection of forest fires at the California Forest and Range Experiment Station were based on the assumption that the visibility of smoke columns in the field would vary as the visibility of the landscape with varying conditions of atmospheric suspensoid concentration and with the position of the sun. This led to the determination of the effect of direction of the sun with respect to the observer's line of sight upon the visibility of natural features in the landscape through analysis of a large number of lookout observations of natural targets on the...

Object To determine the growth rate and net growth, and to determine the rate of restocking after a light, a moderate and a heavy selection cutting.

The conifer forests of the CaUfomia mountains are among the most valuable in North America. The character of the tree species forming the stands, the large dimensions attained by individual trees, the heavy yields, the extensive area occupied, and its comparative accessibihty contribute to high values.

An adequate expression for density of stocking in even-aged forests has long been sought by foresters. Comparison of total basal area of the stand with yield-table values of basal area for the same age and site quality has been the usual method of evaluating stand density. Other methods have been proposed, but none has given results good enough to warrant general adoption or displacement of the basal-area method. It is the purpose of this paper to present a stand-density index which does not require a yield table and which is not affected by possible errors in shape of tho total basal...