Treesearch

Five insect molt inhibitors (MI's) were mixed with artificial diet and fed to 3rd and 6th stage western spruce budworm (Choristoneura occidentalis) larvae and 2nd stage Douglas-fir tussock moth (Orgyia pseudotsugata) larvae. In general, tussock moth larvae were more susceptible that western spruce budworm larvae to these MI's SIR 6874 was by far the most toxic to 3rd and 6th stage western spruce budworm, and diflubenzuron the least toxic. TH 75331 and EL-494 both showed sustantial activity against this insect, while SIR 8514 was relatively less active but was still at least 3 times as...

This guide, based on a literature review and personal contacts, offers recommendations and standards for procedures in reducing losses of residences from wildfires. Possible solutions to the problem of fire protection are discussed in the broad areas of land-use planning and zoning, property development, structural design and construction, landscaping, accessories, occupant activities, and financial incentives. The problem of reducing fire losses in undeveloped areas is also discussed and solutions proposed. The guide is intended for homeowners, lawmakers, and members of the building,...

Three tree improvement programs were analyzed by break-even, cost-benefit technique: one for ponderosa pine in the Pacific Northwest, and two for Douglas-fir in the Pacific Northwest-one of low intensity and the other of high intensity. A return of 8 percent on investment appears feasible by using short rotations or by accompanying tree improvement with thinning. Interest rates, length of rotation, the inclusion of thinnings, and site index had greater effects on profitability than program design. Large breeding zones improved profitability, although they incur the biological risks of...

A disease of Jeffrey pines (Pinus jeffreyi Grev. and Balf.) at Lake Tahoe Basin, California, caused by Elytrodenna disease (Elytroderma deformans) was studied for 7 years after a severe outbreak ofthe fungus in 1971. Among 607 Jeffrey pines on six plots, about one-half were heavily infected and about one-half were moderately or lightly infected in 1971. No uninfected trees were observed. During the 7-year study, about one-half of the trees remained unchanged in vigor, disease intensity, or both, and about one-half decreased in vigor, became more heavily infected, or both. Of the original...

Moisture contents of dead and living fuels are key variables in fire behavior. Accurate, real-time fuel moisture data are required for prescribed burning and wildfire behavior predictions. The convection oven method has become the standard for direct fuel moisture content determination. Efforts to quantify fuel moisture through indirect methods have not been sufficiently site specific. Previous attempts to make direct measurements less time consuming have also been inadequate in one way or another.

Soil N mineralized during 14-day anaerobic incubation at 30°C is evaluated as an index of forest soil fertility and site productivity. Mineralizable soil N determined under standard conditions correlates significantly with N mineralized anaerobically for 6 months in the field, with site index and yield potential of Pinus ponderosa L. growing on volcanic, metavolcanic, and metasedimentary soils, and with foliar concentrations of N. Soils testing less than 12 ppm of mineralizable N are judged clearly deficient, but stands of pine and fir on soils testing as high as 16 ppm of N still may...

This is a listing of the recorded plantings made by the Hawaii division of forestry between the years 1910 and 1960 on government and privately-owned lands within the forest reserves and on certain islands offshore of Oahu. The listing provides: scientific and common names of each plant, type of plant, nomenclature reference, suitability of the plant for Hawaii’s environment, wood quality of those plants that are trees, place of planting by island, forest reserve, and specific location, year planted and the number planted. Indexes include forest reserve maps, location codes, genera by...