Treesearch

Quantification and methods of prediction of wildland fire behavior are discussed briefly and factors of particular relevance to the prediction of fire behavior in Mediterranean ecosystems are reviewed. A computer-based system which uses relevant fuel information and current weather data to predict fire behavior is in operation in southern California. Some of the difficulties encountered in attempts to isolate model and data deficiencies are described.

The use of prescribed fire in the chaparral could reduce the incidence and impacts of severe wildfires and enhance watershed re-sources. This paper describes the operational planning needed for a successful prescribed fire and discusses the recent experience with this technique on the Cleveland National Forest.

The abundance, distribution, and viability of seeds of mamane (Sophora chrysophylla) were determined on study sites within the Mauna Kea Forest Reserve, island of Hawaii. An average of 42 to 305 seeds per m2 were found to a depth of 4 cm. About two-thirds of them were on the soil surface or in the litter. More than 75 percent of the buried seeds were found in the first 2 cm of mineral soil. Over two-thirds of the sample quadrats yielded seeds at some sample depth. Twenty-three to 75 percent of the surface seeds and 18 to 68 percent of the buried seeds germinated.

Information from many sources, published and unpublished, was used in preparing this handbook. The principal source of information was a study in northeastern Oregon conducted as part of the U.S. Department of Agriculture's Expanded Douglas-Fir Tussock Moth Research and Development Program. The purpose of that study was to determine the effects of three chemical insecticides on forest fauna. Results of that study are not reported here, but information about the techniques used for monitoring was drawn primarily from that work.

Fire managers face two interrelated problems in deciding the most efficient use of air tankers: where best to base them, and how best to reallocate them each day in anticipation of fire occurrence. A computerized model based on a mixed integer linear program can help in assigning air tankers throughout the fire season. The model was tested using information from California Division (now Department) of Forestry District 1, which in 1967 maintained a fleet of five aircraft and three air bases. The results confirmed the soundness of the model's mathematical structure and demonstrated that a...

Mature grand firs (Abies grandis [Dougl. ex D. Don] Lindl.) were sampled in two stands, one cutover and one virgin, in the Little Salmon River drainage in west-central Idaho, to estimate stem volume losses associated with topkilling. Damage to the stands resulted from three outbreaks of western spruce budworm (Choristoneura occidentalis Freeman) in 1922-30, 1952-55, and 1969-78. Stems of the firs were dissected and examined for reductions in height and radial growth, stem deformities, and decay associated with topkills. Merchantable volume losses (to a minimum 4-inch diameter top) were...

In fir stands infested with dwarf mistletoe (Arceuthobium abietinum Engelm. ex Munz.), the majority of susceptible understory trees had one or more stem infections. Most stem infections entered through infected branches and grew slowly around the stem, resulting in small amounts of decay or stem killing. Decay was not found in trees less than 50 years old. Despite high rates of stem infection, low rates of decay and stem girdling suggest that stem infections will not lead to serious losses in well-managed young-growth stands. Overstory removal and proper spacing to promote rapid height...

A method is described for developing and evaluating alternatives in land management planning. A structured set of 15 steps provides a framework for such an evaluation. when multiple objectives and uncertainty must be considered in the planning process. The method is consistent with other processes used in organizational evaluation, and allows for the interaction of decisionmakers, specialists, analysts. and the general public. The method incorporates several novel aspects that help in structuring the decision process. Application of the method is illustrated by replicating the development...

Growth and volume data for trees on 25 plots reprsenting 11 introduced species in Hawaii were recorded during a 21-year period. Tree were measured at about 5-year intervals to determine overall growth and stand development. The sites selected were considered better-than-average in terms of elevation, amount of precipitation, and soil quality. Except for redwood, stands were unmanaged. The data reported suggest that 10 tree species can grow fast enough to warrant more extensive plantings for timber or wood fiber production.

Residual effectiveness of nine insecticides applied to bark was tested against western, mountain, and Jeffrey pine beetles. Ponderosa and Jeffrey pine trees were treated and logs cut from them 2 to 13 months later, and bioassayed with the three beetles. The insecticides were sprayed at the rate of 1 gal (3.8 l) per 40- or 80-ft² (3.6 or 7.2 m²) bark surface at varying concentrations. Effectiveness of treatment was based on reduction in length of egg galleries 2 to 3 weeks after initiating bioassay. All chemicals were quite effective for 2 to 13 months, except for malathion and Imidan which...