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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...

Concerns are often voiced about possible environmental damage as the result of the cumulative sedimentation effects of logging and forest road construction. In response to these concerns, National Forests are developing procedures to reduce the possibility that their activities may lead to unacceptable cumulative effects

Abstract - Debris slides over a 20-year period were inventoried on 137,500 acres of forested land in the Klamath Mountains of southwest Oregon. Frequency during the study period was about one slide every 4.3 years on each 1,000 acres-an erosion rate of about 1/2 yd 3 per acre per year Erosion rates on roads and landings were 100 times those on undisturbed areas, while erosion on harvested areas was seven times that of undisturbed areas. Three-quarters of the slides were found on slopes steeper than 70 percent and half were on the lower third of slopes. The study area was subdivided into...

Updating the National Fire-Danger Rating System (NFDRS) was completed in 1977, and operational use of it was begun the next year. The System provides a guide to wildfire control and suppression by its indexes that measure the relative potential of initiating fires. Such fires do not behave erratically–they spread without spotting through continuous ground fuels. Estimates of fire potential have a basis in the mathematical models used for fire behavior. The fire manager must select the fuel model that best represents the fuels in the protection area. Among the 20 fuel models available, not...

This state-of-knowledge report summarizes the best available information on maintenance, restoration, and management of meadows of the Sierra Nevada, California. Major topics discussed include how to classify meadows, meadow soils, productivity of meadows, management problems, and how to evaluate range conditions and trends. Current methods and standards are reviewed, and revised standards for evaluating conditions and trends are suggested. A primary conclusion is that proper meadow management requiresproper range management, including the watershed above meadows and control of user...