Treesearch

Residential encroachment into wildland areas places an additional burden on fire management activities. Prevention programs, fuel management efforts, and suppression strategies, previously employed in wildland areas, require modification for protection of increased values at risk in this interface area. Knowledge-based computer systems are being investigated as knowledge management tools for the organization, synthesis, and application of information pertinent to fire science utilization. Many such systems contain expertise which has been captured from human experts and symbolically...

The San Bernardino National Forest in southern California has recently developed a systematic approach to wildfire prevention planning. However, a comprehensive document or other mechanism for teaching this process to other prevention personnel does not exist. An intelligent tutorial expert system is being constructed to provide a means for learning the process and to assist in the creation of specific prevention plans. An intelligent tutoring system (ITS) contains two types of knowledge--domain and tutoring. The domain knowledge for wildfire prevention is structured around several loci:...

The effects of defoliation level and timing on growth and survival of young loblolly (Pinus taeda L) and slash (P. elliottii Engelm.) pines were studied in pine plantations in 1986. Five defoliation levels (100, 95, 66, 33, or 0 percent) and four defoliation times (January, April, July or October) were replicated at four Coastal Plain locations (two in Georgia and one each in Florida and South Carolina). Needles were manually removed from the ground up through the crown to simulate scorch effects on foliage. Ninety-three percent of the loblolly pines defoliated 100% in October and 40% of...

Prescribed burning beneath standing trees normally requires efforts to protect residual trees from excessive fire damage. Damage to both crowns and boles is strongly influenced by flame length, a fire characteristic functionally related to fireline intensity (Albini 1976). In a good prescribed burn, therefore, the prescription specifies desired or maximum flame lengths consistent with an acceptable level of tree damage, and firing techniques are selected and used so as to achieve those target flame lengths. Backing or strip-head fires, or combinations of the two, are the techniques...

This handbook provides an illustrated reference for identifying the common trees in the forests of Hawaii. Useful information about each species is also compiled, including Hawaiian, English, and scientific names; description; distribution within the islands and beyond; uses of wood and other products; and additional notes. The 152 species described and illustrated by line drawings comprise 60 native species (including 53 that are endemic), 85 species introduced after the arrival of Europeans, and 7 species introduced apparently by the early Hawaiians. The native tree species of Hawaii are...

Twelve-year-old Douglas-fir saplings on the Mad River Ranger District, Six Rivers National Forest, California were released by cutting competing vegetation in a 9-foot radius to test the timing and efficacy of this method in plantations older than those in which such work traditionally is done—the first 5 years. Nine years after release, the average stem diameter (3.60 inches or 9.14 cm) of released Douglas-fir saplings, taken at 12 inches (30 cm) above mean groundline, differed significantly from that of control saplings (2.98 inches or 7.57 cm) (p0.05). In spite of this finding, the...

Total tree height of young-growth red fir can be estimated from the relation of total tree height to diameter outside bark at breast height (DOB). Total tree heights and corresponding diameters were obtained from stem analyses of 562 trees distributed across 56 sampling locations in the true fir forest type of California and Oregon. The resulting equations can predict total tree height as a function of DOB, site index, and stand basal area. Nonlinear regression was used to estimate the equation coefficients. The equations accounted for 70 to 76 percent of the observed variability in total...

Susceptibility of Oregon, California, Nevada, Utah, and Arizona provenances of white fir (Abies concolor [Gord. & Glend.] Lindl.) to crown injury caused by balsam twig aphid (Mindarus abietinus Koch.) was assessed in an experimental plantation in the central Sierra Nevada in California. Bud phenology was observed to explore relationships between flushing times and crown injury. Highest susceptibility occurred in the Oregon provenances, which represented natural populations intermediate between A. concolor and grand fir (A. grandis [Doug.] Lindl). Least susceptibility occurred in provenances...

Local volume tables for ponderosa pine (Pinus ponderosa Dougl. ex Laws. var. ponderosa), sugar pine (Pinus lambertiana Dougl.), Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco), California white fir (Abies concolor var. lowiana [Gord.] Lemm.), and incense-cedar (Libocedrus decurrens Torr.) are presented by 1-inch diameter classes in the range of 3 to 40 inches for ponderosa pine, Douglas-fir, California white fir, and incense-cedar. Sugar pine is presented to 45 inches. Trees were measured by an optical dendrometer. Tables are presented for each species in terms of cubic volume to a 0-...

Response to precommercial thinning in stagnated 55-year-old ponderosa (Pinus ponderosa Dougl. ex Laws.) and Jeffrey pine (P. jeffreyi Grev. and Balf.) stands in northeastern alifornia was rapid and long-lasting. During the first 5 years after thinning, average annual diameter at breast height (d.b.h.) and height growth of trees on the thinned plot was 167 percent and 62 percent greater, respectively, than that of crop trees on the unthinned plot. During the final 12-year measurement period, average annual d.b.h. and height growth of trees on the thinned plot was 43 percent and 38 percent...