Treesearch

Tests to rehabilitate gravel areas in high value recreation sites were carried out by transplanting short-hair sedge (Carex exserta) plugs. The plugs were 1.9 cm (0.75 inch) and 5.1 cm (2.0 inches) in diameter, 10 cm (4.0 inches) deep, and were transplanted in September 1981, with and without papier-mache pots. The test site was Siberian Outpost, in Sequoia National Park, California. Treatments were randomized in 40 quadrat pairs; one quadrat in each pair was fertilized. Results after 1 year showed that the most promising treatment was to transplant large diameter sod plugs unpotted and...

Isozyme phenotypes are described for 45 structural loci and I modifier locus in bishop pine (Pinus muricata D. Don,) and segregation data are presented for a subset of 31 polymorphic loci from 19 enzyme systems. All polymorphic loci had alleles that segregated within single-focus Mendelian expectations, although one pair of alleles at each of three loci showed significant segregation distortion. The consistency of resolution and segregation at many loci in bishop pine makes electrophoretic analyses feasible for many purposes in this species.

Stomach contents have been the major source of dietary information for small birds and other vertebrates. However, killing specimens to look at stomach contents is not an option in studies of endangered species and often is undesirable in other studies. Emetics, causing regurgitation of stomach contents, can be used successfully with small birds, but can stress and even kill them (Prys-Jones et al. 1974, Radke and Frydendall 1974). Collecting or photographing food brought to nestlings may be possible, but only for a limited season and necessarily few individuals. Droppings are produced by...

I censused birds across a moisture gradient in northern Patagonia, Argentina, in the vicinity of Bariloche. Over a 60-km distance, the 12 sites ranged from grassland at lower elevations to upland climax Nothofagus forests of the eastern Andes. Here, I correlated bird abundance and diversities with various vegetation measures. Using all sites, bird diversities and abundances were positively correlated with various foliage measures. When grasslands were excluded, however, an inverse relationship was found: birds were more diverse and abundant in the lower stature shrub communities than in...

Baited toxic trap trees—trunks of living trees sprayed with an insecticide and then baited with an attractive substance—were tested in California to kill western pine beetles attacking ponderosa pine. The attractant was the triplet pheromone mixture of brevicomin, frontalin, and myrcene. Insecticides were lindane, Sevin, permethrin, and deltamethrin. All insecticides were effective at certain concentrations in killing beetles at the baited tree. Adjacent nonbaited trees were often attacked, but such trees were effectively protected with both preattack and postattack sprays. Numbers of...

A key to designing facilities in snowbound areas is knowing what the expected snow load levels are for given recurrence intervals. In California, information about snow load is available only for the Lake Tahoe Basin. About 280 snow courses in the State were analyzed, and snow load estimated and related to elevation on a river basin and statewide level. The tabulated snow load was estimated for three recurrence intervals—25, 50, and 100 years-for each snow course. No relationship was found between elevation and snow load on either a statewide or river basin level.

Given a variable rate of fireline construction and an elliptical fire growth model, two methods for estimating the required number of resources, time to containment, and the resulting fire area were compared. Five examples illustrate some of the computational differences between the simple and the complex methods. The equations for the two methods can be used and programmed to estimate fire size and perimeter, time-to-containment, and the number of resources required as a function of spread rate.

Changes in recreation values after wildfire in the northern Rocky Mountains were determined by estimating the difference in the present net value of recreation activity with and without fire. To estimate the value of recreation activity at burned and unburned sites, a contingent market valuation approach was used. Hypothetical market transactions were created by soliciting bids from recreationists, which they based on photographs of recreation sites depicting scenes before and after two kinds of fire--one of low intensity and the other of high intensity. They were asked what they would pay...

Annual production by deerbrush (Ceanothus integerrimus) and mountain whitethorn shrubs (C. cordulatus) in the south-central Sierra Nevada of California was related to shrub volume, volume squared, and overstory crown closure by regression models. production increased as shrub volume and volume squared increased, and decreased as overstory crown closure increased. The log of production by individual twigs was a function of log of air-dry twig diameter at point of current year's growth (allometric equation). These models were developed for a specific sample of shrubs, but the same independent...

Lindane is registered for remedial control of bark beetles; however, forestry uses are controversial and alternative chemicals are needed. Chlorpyrifos (Dursban 4E), carbaryl (Sevimol 4), and fenitrothion (Sumithion 8E) at 1, 2, and 4 pct active ingredient, and lindane at the registered dosage of 0.6 pct were sprayed on lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) bolts infested with mountain pine beetles (Dendroctonus ponderosae Hopkins) in Colorado. Mean survival ratios (n=10) of the proportions of beetles emerging from treated bolts to the proportion emerging from...