Treesearch

The literature provides limited information on the time of ignition of wood under conditions of rapid heating such as occur in forest and structure fires. An investigation was made of ease of ignition as affected by such physical properties of wood as initial temperature, size, and moisture content and by temperature of ambient gas or rate of heating. Temperature-time history curves are shown for two radii of wood specimens. With the temperature-time data and an equation for unsteady-state heat conduction, the surface temperature of wood when flame appears is calculated. With the method...

Increasing interest in the management of sugar pine (Pinus lambertiana Dougl.) in the mixed-conifer stands of the west slope of the Sierra Nevada has pointed out the need of certain silvical knowledge. One bit of required knowledge is the area that can be seeded effectively by a sugar pine tree. The forest manager must have this information in marking a stand to obtain natural reproduction of sugar pine.

The control of seed-eating rodents, combined with the proper method of cutting and site preparation, appears essential to get the maximum results of natural seeding of pine. One method of control is by treating the area to be regenerated with lethal bait prior to seedfall. This note describes such a method and costs of treatment for the westside and eastside Sierran pine types in California.

In part of the high-site-quality pine and fir types of California, stand improvement cuttings are made especially difficult by the sprouting habit of tanoak (Lithocarpus densiflora Hook. and Arn. ) and madrone (Arbutus menziesii Pursh.). The stumps of these species sprout so vigorously that release of the favored crop trees is only temporary. How to control this sprouting on areas dedicated to production of conifers was the object of a small test on the Challenge Experimental Forest.

In part of the high- site-quality pine and fir types of California, stand improvement cuttings are made especially difficult by the sprouting habit of tanoak (Lithocarpus densiflora Hook . and Arn . ) and madrone (Arbutus menziesii Pursh.). The stumps of these species sprout so vigorously that release of the favored crop trees is only temporary. How to control this sprouting on areas dedicated to production of conifers was the object of a small test on the Challenge Experimental Forest.

A modified embryo culture technique was used to facilitate germination of seed obtained after pollinating sugar pine with pollen from blister rust- resistant Armand and Korean pines. Resulting seedlings appear to be hybrids.

Trees fit into the general rule that (the plants and animals which nature gave us have not been considered quite good enough. For millions of years, it is true, nature has developed a breathtaking variety of forms, each wonderfully adapted to its surroundings. Changes in climate or the conformation of the earth's surface have caused the extinction of some forms and the development and migration of others. But during the long development of civilization man has learned to alter some of the myriad forms of life about him, making them better suited to his needs.

Presented in this Research Note are form-class tables for estimating the volume in board feet, Scribner Rule, of ponderosa pine, Douglas-fir, and white fir in California. This single series of tables fits all three species within acceptable limits of error. It is hoped that this series may satisfactorily replace the many existing tables for single species, both old growth and young growth, and for various sites. The wider application of sales by tree estimates in the national forests of California raises the need for more accurate volume tables. Those now available are based on the two...

Presented here are form-class volume tables giving the volume in board feet, Scribner Rule, for sugar pine and red fir in California. These tables complement the previously published form-class tables for ponderosa pine, Douglas-fir and white fir. The two sets of tables should provide more accurate estimates of individual tree volumes for five of the most important commercial species in California. Much of the text material presented in Research Note 60 has been repeated here in the interest of completeness.

Damages from floods and erosion have been a serious problem in southern California since early pioneer days. The problem is becoming even more serious as the rapidly increasing population and expanding industrial and agricultural development encroach upon the flood plains and extend up the steep slopes and into canyons of the nearby mountains. Protection of forest vegetation from fire is an extremely important factor in maintaining damages at a minimum. The removal of the vegetative cover of the mountain watersheds by fire greatly increases the flood peaks and erosion rates with a consequen...