Treesearch

On fuelbreaks, herbicides have been the primary tool for controlling brush regrowth. Vegetation of low volume and low growth is maintained on these wide strips as an aid to firefighting safety. Goats are a promising alternative to herbicides, and may be the best tool available for controlling brush regrowth on fuelbreaks. They eat a wider variety of plants, and more woody plants, than other livestock. They are less selective on first-year brush regrowth, and more selective as brush is older. Goats should not be expected to control tall, mature brush. A good strategy is sufficient goats to...

This manual describes fast, low-cost biochemical procedures for separating enzymes representing numerous genes of forest trees. During electrophoresis the mixture of enzymes from a megagametophyte or embryo of a germinated seed separates in a gel. Specific stains applied to gel slices locate each enzyme. These procedures expand on those developed for crops research. They provide a means for forest geneticists to get urgently needed information on the amount and geographic distribution of genetic variation in conifers for evaluating species relationships, for protecting rare natural...

Natural pyrethrins and nonhalogenated synthetic pyrethroids are highly active and safe insecticides but are not photostable. A stabilized formulation was developed based on 1% of mixed diarly-p-phenylenediamines in an aromatic solvent. The synthetic pyrethroids bioethanomethrin and resmethrin as well as natural pyrethrins were protected from degradation when exposed to artificial and solar radiation. The photostabilization effect was also confirmed by bioassay against the western spruce budworm.

Fourth-instar larch casebearer, Coleophora laricella (Hübner), was significantly less susceptible to acephate and malathion than were adults of its parasites. Chrysocharis larcinellae(Ratz.) and Dicladocerus nearcticus Yoshimoto (P0.01) than the hosts to diflubenzuron. Malathion was equally toxic to both parasite species. D.nearcticus appeared to be the more tolerant of the parasites to both acephate and diflubenzuron.

Remote sensing techniques were investigated as an alternative for documenting selected prettack fire planning information. Locations of fuel models, road systems, and water sources were recorded by Landsat satellite imagery and aerial photography for a portion of the Six Rivers National Forest in northwestern California. The two fuel model groups used were from the 1978 National Fire Danger Rating System and the Northern Forest Fire Laboratory. Landsat-derived fuel model data were digitized and computer analyzed by unsuperivesed and guided clustering techniques to produce a fuel model map...

Monoterpene composition was studied in a number of hard pine species and results were compared with earlier work. (1) Intratree measurements showed strong constancy of composition in both single-stemmed and forked trees of ponderosa, Jeffrey, Coulter, and Jeffrey x ponderosa pines. In grafts of these and other pines, the scion influenced the root stock, but not the reverse. (2) Large intertree variation in composition was found in a small sample of seven hard pines native to Mexico; the value of monoterpenes in clarifying taxonomy of these pines remains uncertain. (3) An 80-tree plot of...

Some field studies of the effects of various insecticides on the spruce budworm (Choristoneura sp.) and their parasites have shown severe suppression of host (budworm) populations and increased parasitism after treatment. Computer simulation using hypothetical models of spruce budworm-parasite systems based on these field data revealed that (1) effective parasites produce greater stability in budworm populations than ineffective ones and are more resistant to changes induced by insecticides; and (2) the level of budworm population suppression in most budworm-parasite systems is not...

A sample of 231 independent timber investments were ranked by internal rate of return, present net worth per acre and the benefit cost ratio—the last two discounted by 3, 6.4. 7.5. and 10 percent—to determine if the different criteria had a practical influence on timber investment ranking. The samples in this study were drawn from a group of timber investments partially financed by Forestry Incentives Program costshare funds. The investment rankings were quite similar among the three criteria. Under constrained investment budgets, the benefit / cost criteria produced the investment...