Treesearch

Abstract - Although experimental watershed studies have consistently shown that water yield can be increased by removing trees and shrubs, programs to increase water yield on an operational scale have consistently failed. Failure has been related to overstated goals and benefits, unrealistic assumptions, political naivete, and the emergence of new interest groups. There is every indication that management of vegetation for increased water yield will continue to be impractical

The fire program planner faces an increasingly complex task as diverse--and often contradictory--messages about objectives and constraints are received from political, administrative, budgetary, and social processes. Our principal challenge as we move into the 21st century is not one of looking for flashier technology to include in the planned fire program. Rather, we must give major attention to the development of a better, more effective understanding by politicians, administrators, and the general public of the fire program alternatives available, their risks, and their real social,...

Breeding bird communities were studied in 32 forest islands surrounded by urban development. These isolated woodlands in Springfield, Massachusetts, provided breeding habitats for a wider variety of birds (77 species) than previously described for other urban habitats (e.g. four times as many species as found in urban residential areas in the same city in a previous study). The size of the woodland was the primary influence on bird diversity in these wood-lands, explaining 79 and 75% of the variation in total species richness and the Shan- non-Weaver index of bird species diversity,...

Abstract - New understanding of how steepland channels formed is being pursued over a large range of scales, from entrainment of bed particles to the transfer of stored sediment down channel systems. Low submergence of bed particles during transport and wide heterogeneity in particle sizes strongly affect bedload transport. At the scale of a reach, scour-lobes are becoming widely recognized as common constructional units governing behavior of braided, meandering, and pool-riffle channels. Channel morphology and sediment transport can be radically altered by infrequent debris flows and...

Abstract - High-magnitude, low-frequency discharges are more responsible for transporting suspended sediment and forming channels in northwestern California than in previously studied areas. Bankfull discharge and the magnitude and frequency of suspended sediment discharge were determined at five gaging stations in northwestern California. Although discharges below which 50 percent of the suspended sediment was transported and discharges which transport the greatest suspended sediment (effective discharge) occurred relatively frequently, recurrence intervals for these discharges were...

As vital components of habitat for stream fishes, pools are often monitored to follow the effects of enhancement projects and natural stream processes. Variations of water depth with discharge, however, can complicate monitoring changes in the depth and volume of pools. To subtract the effect of discharge on depth in pools, residual depths can be measured. Residual depth is the difference in depth or bed elevation between a pool and the downstream riffle crest. Residual pool depth or volume can be measured at wadable flows by using only a tape and graduated sounding rod. Residual dimensions...

Wildfires do not respect property boundaries. Whole geographic regions are typically impacted by major wildfire outbreaks. Various fire related resources can be shared to solve such crises; whether they are shared, and how they are shared depends to a great extent upon the rapport among the agencies involved. Major progress has been achieved over the past decade largely through the adoption of some formalized processes, such as the National Wildfire Coordinating Group. More progress can be made on into the 21st century at the local, state, and national levels if managers will support the...

This Guide presents taxonomic keys based on vegetative features of 132 southern California shrub and subshrub species found in an area bounded by the southern part of the coast ranges, the north and east sides of the transverse and peninsular ranges, and Mexico. The keys are supported with instructions and an extensive glossary. Species discussion includes a brief description and generalized distribution of each species. When known, the fire response mechanism, wildlife value, and cultural value are given. A line drawing or photograph of each species is included. All genera that include...

Fire is a common occurrence in the California chaparral. Aside from brush removal through combustion, physical changes also take place in the soil during fire. These changes lead to accelerated erosion rates which begin almost immediately and continue through the next 5 to 10 years (Rowe and others 1954; Wells and Brown 1982). Since the late 1940's seeding burned slopes with ryegrass for the purpose of quick revegetation and erosion reduction has been a common practice. It is generally easier and less expensive than mechanical means of dealing with the erosion problem.