Treesearch

Without effective, economic techniques to control regrowth of brush, permanent modification of large areas of chaparral to a stable cover of low fuel volume is virtually impossible. The aggressive reestablishment of most brush species after top removal will soon cancel out any value of an initial clearing operation. In 2 years, regrowth may attain a height of several feet. Grass or other cover being established for soil protection is rapidly crowded out. Practically all of the brush plants--except those left for esthetic purposes--must be eliminated. If they are not, reclearing is necessary...

"How much will it cost?" This question is asked in the planning stage of every brush conversion. "To bulldoze? To spray? To seed?" Frequently there is no experienced person standing by to answer. To provide-such information, we have assembled notes and figures from fuel-break studies at the San Dimas Experimental Forest, and from brush conversion projects by the California Division of Forestry, the National Forests in southern California, and the Los Angeles County Fire Department.

Critical appraisal of dwarf mistletoe damage and of rate of spread and intensification may depend on knowledge of mistletoe population characteristics. Studies of dwarf mistletoe (Arceuthobium campylopodum) on red fir (Abies magnifica) were made by cutting and examining 14 trees 24-86 years old (avg 58). Bole infections, tallied separately, were found on all but 1 tree and averaged 2.2/tree. Of the 1,299 branch infections examined, 23% were dead. Of the remaining live infections, 51% bore shoots, 18% bore fruit, and only 5% bore large fruiting clumps. These observations indicate that only...

Stands of red fir and white fir in California are extensively infected with the fir dwarfmistletoe, and damage is heavy over much of the fir belt. Field observations and cross-inoculation studies show that there are two specialized forms of fir dwarfmistletoe, one attacking only red fir and one only white fir. In most fir stands, only one form is present in a given area. In such stands, reduction of mistletoe damage through stand conversion or through selective thinning of reproduction is suggested. Where both forms of mistletoe are present in the same stand, standard control procedures or...

Late model helicopters equipped with new helitanks and adequately supplied can accurately deliver as much fire retardant as most fixed-wing air tankers at a potentially lower cost. Viscous water dropped from helicopters clung to fuel surfaces and was concentrated in a narrower pattern than plain water.

Operational tests conducted from air tanker bases in California in 1962 confirmed earlier laboratory and field studies and showed that viscous solutions of diammonium phosphate (DAP) are more effective than any other presently known fire retardant. These tests also indicated that corrosion is not a serious problem if inhibitors are used and equipment is properly maintained. Some storage problems still remain.

Soil pore volume and pore size were correlated with land use or vegetation cover type. The top foot of forest soils had more large pores and higher water-holding capacities than that of soils under cultivation, in pasture land, or in idle grassland.

In the first year of studies of moisture in living fuels, pine and manzanita had dissimilar moisture trends, the moisture content of brush varied with elevation during the growing season, and soil moisture was correlated with brush foliage moisture.

This review article presents a summary of the knowledge of pyrolysis of cellulose and the factors that affect it.

Ponderosa pine, the preferred species, accounted for only 15 percent of the residual coniferous reproduction in seed-tree cuttings. Logging slash was machine-piled to encourage pine regeneration. Slash piling reduced the percentage of plots stocked with conifers from 38 to 12 percent. It destroyed 90 percent of the youngest seedlings but only 27 percent of the saplings from 2.0 to 3.5 inches d.b.h.