Treesearch

The exotic goldspotted oak borer (GSOB), Agrilus auroguttatus (Coleoptera: Buprestidae), continues to cause elevated oak mortality in southern California. Initial GSOB research was directed at developing an integrated pest management program. However, little research has examined the secondary impacts associated with this invasive pest. My primary objective was to compare the fuel loading in severely GSOB-infested woodlands (>10 years of oak mortality) to uninfested woodlands in southern California. Forest stand characteristics, canopy fuels, understory fuels, and surface fuels were...

Private land plays a crucial role in the conservation of biodiversity in California, yet these lands are the least protected and most prone to environmental degradation. In 1930, Aldo Leopold recognized the potential to better conserve private land by an incentive scheme where recreational users would pay landowners for access to conserved wildlife habitat. While research has shown that significant funds are spent to utilize large areas of private land for wildlife-associated recreation, this study seeks to specifically understand whether this recreational use actually results in improved...

Oak acorns have historically provided food for humans and animals in cultures across Asia, North Africa, Europe, and North America. The advent of the twentieth-century saw acorns become marginalized as a food crop in the United States and most of the world, but they have remained a constant part of the cuisine of the Korean Peninsula. Consequently, Korea is often cited when discussing the potential of a commercial acorn industry in California, yet little is actually known about acorn production in Korea. This is a report of preliminary results from a project conducting interviews across...

To better understand forage production (above ground biomass) and precipitation patterns in the Central Coast region of California, the first in a growing network of primary production monitoring sites were established in 2001. The California Central Coast has a Mediterranean climate with cool, moist winters and hot, dry summers, and is dominated by annual grasslands and oak woodlands. By 2010, 12 sites were established across San Luis Obispo County, stratified by different rainfall zones, greater than 635 mm (coastal) to less than 200 mm (inland) for an average year. Forage production was...

Ecological site descriptions and associated state-and-transition models are useful tools for understanding the variable effects of management and environment on range resources. Models for woody riparian sites have yet to be fully developed. At Tejon Ranch, in the southern San Joaquin Valley of California, we are using ecological site theory to investigate the role of two managed ungulate populations, cattle and feral pigs, on riparian woodland communities. Responses in plant species composition, woody plant recruitment, and vegetation structure will be measured by comparing cattle and...

Rangelands are estimated to cover 30 to 50 percent of the world's land surface and have significant belowground carbon (C) storage potential. Given their geographical extent, many have suggested that even modest changes in C storage via management practices could alter the global C cycle, creating climate change mitigation opportunities. Our objective was to investigate soil organic carbon (SOC) stability across a managed annual grassland, savanna, and oak woodland landscape. We sampled A and AB horizons from 20 soil profiles to assess long-term SOC stabilization pathways using combined...

An ongoing study of the small wetlands in the northern Sierra Nevada foothill oak woodlands that provide habitat for the state-threatened California black rail (Laterallus jamaicensis coturniculus) offers an example of the way that the social ecological systems (SES) framework can be used to analyze a natural resource problem. At the outset, it was hypothesized that the area's hydrology, West Nile Virus from wetland mosquitos, the population ecology of the bird, and the decisions of landowners would have important impacts on the wetlands and birds. A SES framework was applied to identify...

We apply an ecosystem accounting system to estimate the total social income accrued from private and public products in a group of agroforestry farms in Andalusia (Spain). We provide bio-physical and economic indicators for two contrasting farm types, a sub-group of 15 publicly owned coniferous forests and a sub-group of 24 privately owned dehesa farms. Total social income attained, in 2010, an average value of €140 per hectare in public forests and €352 per hectare in private dehesas. In public forests, social and environmental targets prevail over the demand for revenues from agroforestry...

California oak woodland creates a landscape of renowned beauty, providing the public with essential natural resource services and economic values through ranching. Ranchers however, come under intense pressure and scrutiny from the public to demonstrate stewardship of the land they manage. The solution often chosen to address these concerns is, simply, more regulations. Regulations impose a financial and philosophical burden on California ranchers; in fact, they threaten the very existence of ranching. This paper discusses the development and on-going implementation of the Ranching...

The prospect of changing climate has led to uncertainty about the resilience of forested mountain watersheds in the tropics. In watersheds where frequent, high rainfall provides ample runoff, we often lack understanding of how the system will respond under conditions of decreased rainfall or drought. Factors that govern water supply, such as recharge rates and groundwater storage capacity, may be poorly quantified. This paper describes 8-year data sets of water stable isotope composition (d2H and d18O) of precipitation (4 sites) and a stream (1 site), and four contemporaneous stream sample...