William E. Frost

Tree canopy effects on herbaceous production of annual rangeland during drought

Seasonal herbaceous production was measured beneath tree canopies of blue oak (Quercus douglasii Hook & Arn.), interior live oak (Quercus wislizeniiDC), and digger pine (Pinussabiniana Dougl.), and in adjacent open grassland during 2 drought years (1986-87 and 1987-88) at the San Joaquin Experimental Range, California. Early and mid-growing season herbaceous production was variable, with no increase in production beneath the canopies the first year and a 60 to 150 kg/ha increase the second year compared to the herbage produced in open grassland. Peak standing crop was about 1,000 kg/ha greater beneath blue oak canopies than in open grassland in both years. Peak standing crop beneath interior live oak canopies was about 700 and 1,000 kg/ha greater than in open grassland the first and second years of the study, respectively. Peak standing crop beneath digger pine canopies was about 500 kg/ha greater the first year and similar the second year to that of the open grassland.

Effects of tree canopies on soil characteristics of annual rangeland.

In the central California region of annual rangeland, herbage production beneath blue oak (Quercus douglasii Hook & Arn.) canopies is greater and production beneath the canopies of interior live oak (Quercus wislizenii DC) and digger pine (Pinus sabiniana Dougl.) is less than that in adjacent open grassland. The objective of this investigation was to assess the impact of these major overstory species on soil-associated characteristics in an effort to explain this tree-herbage production relationship. Greater amounts of organic carbon (OC), greater cation exchange capacity (CEC), lower bulk density, and greater concentrations of some nutrients were found beneath blue oak canopies than in open grassland. This explains, at least in part, the increased herbage production beneath blue oak canopy.

Determining the Effects of Cattle Grazing Treatments on Yosemite Toads (Anaxyrus (=Bufo) canorus) in Montane Meadows

Amphibians are experiencing a precipitous global decline, and population stability on public lands with multiple uses is a key concern for managers. In the Sierra Nevada Mountains (California, USA), managers have specifically identified livestock grazing as an activity that may negatively affect Yosemite toads due to the potential overlap of grazing with toad habitat. Grazing exclusion from Yosemite toad breeding and rearing areas and/or entire meadows have been proposed as possible management actions to alleviate the possible impact of cattle on this species. The primary objective of this study was to determine if different fencing treatments affect Yosemite toad populations. We specifically examined the effect of three fencing treatments on Yosemite toad breeding pool occupancy, tadpoles, and young of the year (YOY). Our hypothesis was that over the course of treatment implementation (2006 through 2010), Yosemite toad breeding pool occupancy and early life stage densities would increase within two fencing treatments relative to actively grazed meadows due to beneficial changes to habitat quality in the absence of grazing. Our results did not support our hypothesis, and showed no benefit to Yosemite toad presence or early life stages in fenced or partially fenced meadows compared to standard USDA Forest Service grazing levels. We found substantial Yosemite toad variation by both meadow and year. This variation was influenced by meadow wetness, with water table depth significant in both the tadpole and YOY models.

Using GIS in Agricultural Land Assessment for Property Taxes

Abstract This study illustrates the application of range productivity models across a broad spatial scale. A series of relevant data layers for these range models were constructed using photo-interpretation and digital elevation models. A geographic information system was used to merge the data layers to evaluate total livestock carrying capacity for individual land parcels. This approach has application for county tax assessors interested in a scientific basis for appraising rural land values. The study was carried out in the foothills of Californias San Joaquin Valley in response to policy concerns raised about the implementation of the California Land Conservation Act, a property tax system designed to conserve agricultural and open space values.