Treesearch

Synopsis - Examples from California are used to illustrate typical responses to erosion and debris flow disasters the United States. Political institutions leave virtually all responsibility for disaster prevention to the lowest levels of government or to individuals. Three circumstances in which disasters occur are discussed: urbanized debris cones, urbanized unstable landforms, and logging of unstable terrain. By far the greatest economic losses result from the urbanization of unstable landforms. These losses occur not because of a lack of appropriate mitigative technology, but as the...

Examples from California are used to illustrate typical responses to erosion and debris flow disasters in the United States. Political institutions leave virtually all responsibility for disaster prevention to the lowest levels of government or to individuals. Three circumstances in which disasters occur are discussed: urbanized debris cones, urbanized unstable landforms, and logging of unstable terrain. By far the greatest economic losses result from the urbanization of unstable landforms. These losses occur not because of a lack of appropriate mitigative technology, but as the result of...

Two types of problems are related to collecting hydrologic data at stream gaging stations. One includes the technical/logistical questions associated with measuring and transferring data for processing. Effort spent on these problems ranges from improving devices for sensing data to using electronic data loggers.

Measuring suspended sediment concentration in streams provides a way of monitoring the effects of forest management activities on water quality. Collecting data on suspended sediment is an act of sampling. The nature of the delivery process and the circumstances under which data are collected combine to produce highly variable results that are difficult to analyze and interpret. Data-collection stations are set up to compare one set of measurements to another. They should be located with regard to channel morphology. Deciding when to measure suspended sediment is a major problem in...

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; Newell 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...

Methods were devloped for rearing Glypta fumiferanae Viereck on a nondiapausing laboratory colony of the western spruce budworm, Choristoneura occidentalis Freeman. Both host and parasite are univoltine and undergo diapause in nature. In this study, the parasite's voltinism was synchronized with that of a nondiapausing host. G fumiferanae mated readily in the laboratory, and 5 consecutive generations were reared with an average generation time of less than 8 weeks-much less that the 23 weeks needed for 1 generation to develop in the field. Developmental times are reported, and some aspects...

Species trials have been conducted in Hawaii since the 1870's. Many species have been successfully established and harvested, whereas native species have failed in numerous reforestation projects. Since the early 1960's silviculture research concentrated on developing methodology for establishing and developing forest stands for timber production.

Water yield and sediment production almost always increase after wildfire has destroyed vegetative cover. The value of water generally is not as much appreciated in the water-rich northern Rocky Mountains as it is elsewhere. Increased water yield becomes economically beneficial, however, when its potential for consumptive and nonconsumptive uses is realized. Whether the effects of increased sedimentation are aesthetic, biological, physical, or economic, they are usually detrimental.