Treesearch

Although sucrose and cellulose are both carbohydrates of basically similar composition, the very materials which have been found to be most effective in preventing flaming combustion of cellulose are also effective in causing sugar cubes to support flame.

Old-growth timber is still the main source of ponderosa pine sawlogs in California, but the proportion of the annual cut from young-growth sawtimber is expected to rise rapidly in the future. The increasing significance of the young-growth resource is particularly apparent in the westside Sierra subregion, where the Challenge Experimental Forest is located. In this subregion, almost 20 percent of the annual softwood sawtimber growth on commercial forest land is in young-growth sawtimber.

In a dense forest that has been thinned recently there are often some tree stumps that are still alive and growing despite the loss of their green tops. Such stumps have been noted for many years and are known to be products of root-grafting between trees (Bormann and Graham 1957). If light cutting or windfall occurs in a dense stand where root-grafting is common, food materials in the standing members of a grafted clump will move through root-grafts into the fresh stumps. Thus the cambium of a stump can continue to add increments of wood and bark. This paper reports on studies of the...

Board foot volumes have been determined for ponderosa pine, sugar pine, white fir, and Douglas-fir in 90-year-old mixed-conifer stands on the Challenge Experimental Forest, near Oroville, California. Productivity is high—site index 140 feet at 100 years. Following the technique described by Boe, the scaled volumes of felled trees were plotted on logarithmic graph paper against the volumes for the same species in the Region 5 Volume Tables.

A program of research on free-burning wood fires is being conducted by the Forest Service to build up experimental data on the properties of such fires, with the iltimate objective of describing the physical phenomena in terms of fundamental laws. Density was the first wood property investigated. This report gives data on the rate of burning of cribs of five species of wood, each of several density classes. Thermal diffusivity values of the wood were also estimated and correlated with the rate of burning.

A laboratory study was set up by the U.S. Forest Service with the ultimate objective of determining model laws for properties of wood fires, including rate of spread. This is a report of the first phase of the work, the development of a suitable bed of solid fuel and the technique of study. The bed chosen for initial study is in the form of long cribs of wood sticks. The technique is to start the crib burning at one end and to move the crib so as to keep the flame in a fixed position in space. Thermocouples in the convection column, radiometers, Pitot tubes, gas sampling tubes, and other...

People used to think that 150 years was about the maximum lifespan of the most durably viable seeds.

Early returns from a study of altitudinal variation of pines along an elevational transect in California indicated middle elevation sources grew best regardless of the elevation of planting, seeming to contradict the old maxim, "Local seed source is best" (6). Later returns bring some support for the maxim as local seed sources assert them selves after 20 years. Nonlocal seed sources do not keep up the growth pace or are hard hit by environmental factors.

Sowing with a drill is the best way to obtain the good grass stands needed for soil protection on fuel-breaks or for forage on rangeland where brush has been removed. Two years of testing have shown this is true in southern California, as longer experience has proved for other kinds of land in the West. In fact, the adequate stands obtained from drilling in all tests during two extremely dry years convinces us that we can establish perennial grasses consistently on fuel-breaks wherever a drill can be used.