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The mountain pine beetle (Dendroctonus ponderosae Hopkins) is the most destructive insect that attacks lodgepole pine (Pinus contorta Dougl.), a species valued for multiple uses throughout North America. The effective residual life of carbaryl, applied as a 2 percent suspension of Sevimol to the bark of lodgepole pine to prevent attack by mountain pine beetle, was evaluated near Dillon, Colorado. Trees (9,568) treated in 1982 under operational conditions were used to assess the efficacy of the treatment for one and two beetle flight periods after insecticide application. Estimated mortality...

A programmable calculator connected to an interface circuit can control automatic samplers and record streamflow data. The circuit converts a voltage representing water stage to a digital signal. The sampling program logs streamflow data when there is a predefined deviation from a linear trend in the water elevation. The calculator estimates suspended sediment discharge from rating coefficients for the gauging site. When a threshold value of accumulated suspended sediment discharge is reached, the calculator sends a signal to the interface circuit that activates a pumping sampler. The...

Two Eucalyptus species-E. saligna Sm. and E. grandis Hill-are especially favored in Hawaii forwood, fiber, and fuel production because of their quick growth and high yields. Their growth is limited, however, on many sites by low levels of available nitrogen. Supplemental nitrogen can be provided by nitrogen-fixing plants, such as legumes. A test was conducted to determine whether planting two leguminous species-Acacia melaxylon R. Br. and Albizia facataria (L.) Fosberg-could increase biomass production. Results after 65 months suggest that Eucalyptus growth can be increased substantially...

This report provides a guide to techniques for designing field tests of candidate insecticides, and for carrying out pilot tests and control projects. It describes experimental designs for testing hypotheses, and for sampling trees to estimate insect population densities and percent reduction after treatments. Directions for applying insecticides by aircraft and for evaluating the effectiveness of such applications on target and nontarget insects are explained. The guide can help practitioners improve decisionmaking, efficiency, and safety in the use of insecticides to control forest...

Much of the work on life history evolution in plants has dealt with allocation of reproductive effort (Abrahamson 1975; Abrahamson and Gadgil 1973; Gaines et al. 1974; McNaughton 1975; Oka 1976; Stearns 1976, 1977, 1980; Newel1 and Tramer 1978; Primack 1979). The juvenile period, however, occupies a major and critical portion of the life cycle of many species. Allocation of growth among vegetative organs during the juvenile period may place constraints on later development. The work of Marks (1975) and others (Troughton 1960; Monk 1966; Harper 1977; Pitelka 1977; Abrahamson 1979) suggested...

Synopsis - Data collected from 299 road segments in northwestern California were used to develop and test a procedure for estimating and managing road-related erosion. Site conditions and the design of each segment were described by 30 variables. Equations developed using 149 of the road segments were tested on the other 150. The best multiple regression equation explained only 37% of the variance in the logarithm of road-related erosion. A discriminant analysis correctly classified 74% of the test data set. Road segments it predicted to be hazardous produced 82% of the measured erosion in...

Abstract - A linear discriminant function, developed to predict debris avalanches after clearcut logging on a granitic batholith in northwestern California, was tested on data from two batholiths. The equation was inaccurate in predicting slope stability on one of them. A new equation based on slope, crown cover, and distance from a stream (retained from the original equation) predicted stability on all three batholiths with an overall accuracy of 83 percent. A procedure is described that can be used to decide how to harvest slide-prone slopes. The procedure uses the manager's estimates of...

Abstract - Hydrograph lag time was analyzed to determine changes after road construction and after selective, tractor-yarded logging in a Caspar Creek watershed, Mendocino County, California. The paired watershed technique was used. Hydrograph lag time for each storm was the time separation between the midpoint of precipitation and the time coordinate of the runoff centroid. No significant change in lag time was detected after road construction. After logging, the lag time generally increased for small, early fall storms and decreased for larger storms. To determine whether the change...

Abstract - The effects of road building and selective tractor harvesting on storm peak flows and storm volumes were assessed for a small (424 hectare) coastal watershed in Northern California. Two watersheds, the North and South Fork of Caspar Creek were calibrated from 1962 to 1967 while no treatments took place. Roads were then built on the South Fork, and the two watersheds were monitored until 1971. Between 1971 and 1973 the South Fork was selectively tractor logged, removing 60 percent of the timber volume. The storm flows were monitored until 1976. Only the very small (566 l/s or...

The ""Selection At List Time"" (SALT) scheme controls sampling of concentration for estimating total suspended sediment yield. The probability of taking a sample is proportional to its estimated contribution to total suspended sediment discharge. This procedure gives unbiased estimates of total suspended sediment yield and the variance of the estimate while automatically emphasizing sampling at higher flows. When applied to real data with known yield, the SALT method underestimated total suspended sediment yield by less than 1%, whereas estimates by the flow duration sediment rating curve...