Treesearch

The family Mustelidae is large and many mustelid species guilds are larger than other carnivore guilds. For example, in northeastern North America half the native carnivore species are mustelids (Hail 1981). Though competition between mustelids has not been proven (vis-a-vis Connor & Simberloff 1979), mustelid sympatry has always been explained by size differences that reduce competition for food (Rosenzweig 1966). We find it difficult to believe that size differences alone explain the coexistence of so many mustelids, especially in the genera Martes and Mustela.

WNDCOM is a mathematical model for estimating surface winds in mountainous terrain. By following the procedures described, the sheltering and diverting effect of terrain, the individual components of the windflow, and the surface wind in remote mountainous areas can be estimated. Components include the contribution from the synoptic scale pressure gradient, the sea breeze, the slope wind, and the valley wind. For each component, a brief description, the data and information needed for estimation, and step-by-step procedures are provided.

The analysis of alternative fire management programs should be integrated into the land and resource management planning process, but a single fire management analysis model cannot meet all planning needs. Therefore, a set of simulation models that are analytically separate from integrated land management planning models are required. The design of four levels of fire management analysis that contribute to the planning process has been developed. The interactions among these four levels and between the fire management analysis and the planning process are designed for consistency and...

Urban encroachment into chaparral areas has accelerated the fire-flood-erosion cycle. Preventative maintenance measures can help reduce the damage from fire and flood. This report describes the chaparral environment; how to cope with problems in watershed management, how to landscape for fire and soil erosion control, how to plan for home safety from fire, how to treat newly burned chaparral slopes, how to clear brush around homes; and what to do when caught in a wildfire. The information reported is addressed to homeowners, buyers, and developers; and architects, planners, and other...

A taxonomic Vegetation Classification System proposed for use in California is designed to simplify interdisciplinary communication about vegetation. The system structure is an aggregative plant community hierarchy at four levels of precision--the Association, Series, Subformation, and Formation. A flexible Phase category links specific resource management concerns to the system. The System is based on the concept of vegetation as an ecological component, and is neutral with respect to management function; design criteria stem from performance needs and principals of classification. The...

The symposium, held at San Diego State University, provided information about the Mediterranean-type ecosystems found throughout the world. In the papers, and in brief summeries of poster displays, both researchers and managers addressed concerns relating to vegetation, fauna, soils, hydrology, fire, and planning. A Review and Follow-up section presents general comments of selected participants.

Young red firs (Abies magnifica A. Murr.) and white firs (A. concolor [Gord. & Glend.] Lindl. ex Hildebr.) on the Stanislaus National Forest, California, were inoculated with seeds of dwarf mistletoe (Arceuthobium abietinum) for 5 successive years. Only 3 to 4 percent of about 7000 seeds placed on branches resulted in infections. Second-generation infections developed and populations of the parasite built up on some trees but not on others after 17 years. Variables that appeared to regulate population increases included an 8- to 9-year average between inoculation and fruiting of plants,...

Researchers are not agreed on the effects of logging on lag time. Numerous studies have shown that the use of heavy equipment in logging operations can cause soil compaction. Also, associated roads alter natural drainage patterns by concentrating runoff and interrupting subsurface flow. As a result these researchers say, less infiltration into the soil takes place after treatment than in the undistrubed condition. In addition, the increased overland flow my be accelerated due to the development of waterways such as erosion rills or the removal of channel obstructions. A sorter lag time...

A simple Monte Carlo simulation evaluated the effect of several fire management strategies on soil slip erosion and wildfires. The current condition was compared to (1) a very intensive fuelbreak system without prescribed fires, and (2) prescribed fire at four time intervals with (a) current fuelbreaks and (b) intensive fuel-breaks. The intensive fuelbreak system caused a slight increase in soil slip erosion and a reduction of about 12 percent in average annual wildfire area associated with each of the prescribed fire intervals. All of the prescribed fire strategies greatly reduced...

Quantification and methods of prediction of wildland fire behavior are discussed briefly and factors of particular relevance to the prediction of fire behavior in Mediterranean ecosystems are reviewed. A computer-based system which uses relevant fuel information and current weather data to predict fire behavior is in operation in southern California. Some of the difficulties encountered in attempts to isolate model and data deficiencies are described.