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1 Sudden oak death is caused by the apparently introduced oomycete, Phytophthora ramorum. We investigated the role of bark and ambrosia beetles in disease progression in coast live oaks Quercus agrifolia . 2 In two Marin County, California sites, 80 trees were inoculated in July 2002 with P. ramorum and 40 were wounded without inoculation. Half of the trees in each group were sprayed with the insecticide permethrin [cyclopropanecarboxylic acid, 3-(2,2-dichloroethenyl)-2,2-dimethyl-(3-phenoxyphenyl) methyl ester] to prevent ambrosia and bark beetle attacks, and then were sprayed twice per year thereafter. After each treatment, sticky traps were placed on only the permethrintreated trees. Beetles were collected periodically in 2003. 3 Inoculated trees accounted for 95% of all beetles trapped. The ambrosia beetlesMonarthrum scutellare and Xyleborinus saxeseni and the western oak bark beetle Pseudopityophthorus pubipennis were the most abundant of the seven species trapped. 4 Permethrin treatment delayed initiation of beetle attacks and significantly reduced the mean number of attacks per tree. Beetles did not attack any wounded or noncankered inoculated trees. 5 Trees with larger cankers trapped more beetles early in the disease. Once permethrin lost effectiveness, the number of beetle entrance tunnels was a more reliable predictor of subsequent trap catch than was canker size. 6 Beetles were initially attracted to P. ramorum cankers in response to kairomones generated in the host-pathogen interaction. After beetles attacked the permethrintreated trees, aggregation pheromones most probably were the principal factor in beetle colonization behaviour.bark and ambrosia species accelerates tree mortality by introducing fungi deep into the sapwood, directly (by vectoring) and/or indirectly (by creating tunnels).

An empirical bioeconomic model was developed for private ranches conducting firewood, cattle, and hunting enterprises on California's hardwood rangelands. Hunting, forage, cattle, and oak firewood production functions were derived. Nonlinear optimal control was used to solve for two state and four control variables to give optimal time pathways for oak density and cattle stocking. Risk was considered through use of chance constraints, rainfall variability, and price expectations. Commercial hunting is shown to be the dominant economic value on these rangelands. Inclusion of stochastics shifts production away from cattle to less risky firewood and hunting enterprises.

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The importance of evaluating multiple resource values on rangelands is demonstrated in this study of California's 3.0 million hectares of oak-covered (Quercuz spp.) hardwood rangelands. Production functions are derived for oak tree growth on rangelands for stands with at least 50% of the total tree cover in blue oak (Quercus doughii Hook. & Am.) based on oak volume per acre and site index. Forage production is estimated based on oak cover, weather variables, growing period, and site factors from data reported in the literature. Hunting revenue and cost functions are derived from a survey of commercial hunting clubs, and are based on oak cover, hunter success variables, hunter demographics, advertising, livestock density, and club size. The interrelationship of these resource values is shown in output from an optimal control model that incorporates these production functions. Oak trees are gradually cleared for situations where cattle are the only economic product, whereas a residual tree canopy is maintained for cases where firewood and hunting enterprises are considered. In addition, cattle stocking is higher and net profitability is lower for the cattle only management scenario when compared with a multiple use management scenario. The development of these multiple use production functions allows the full range of resource management options to be considered. Key Words: range economics Rangelands provide a variety of valuable resources such as wildlife habitat, aesthetics, recreation, forage, and watershed protection Increasingly, economic and policy analysis of rangelands requires that all of these resources are adequately assessed in order to evaluate likely acceptable management practices and long-term resource values. However, production functions for these diverse resource values often do not exist, nor are the interrelationships among different resources known. California's oak woodlands, also known as hardwood rangelands, are an example of a rangeland system where a variety of resource values are important and where there has been little analysis of the multiple resource values. This absence of detailed information has not prevented multiple resource values from being advocated. These rangeland areas occupy an estimated 3.0 million hectares in the state (Bolsiner 1988). Hardwood rangeland areas have at least a 10% canopy of hardwood tree species, predominantly in the oak genus (Quercus spp.), with an understory of annual grasses. Griffin (1978), Bartolome (1987), and Holmes (1990) provide good descriptions of these areas. Historically, these areas have been managed primarily for livestock production. In addition, hardwood rangelands are important in providing critical habitat for many game and nongame wildlife species (Verner

Sudden oak death is a disease affecting coastal forests in California and southern Oregon. The spatial pattern of disease dynamics is important for forest and landscape pathology; in this work we investigated the interaction across landscape scales of disease symptomology in coast live oaks, Quercus agrifolia, (trunk bleeding, presence of beetles, and presence of the fungus Hypoxylon thouarsianum) and tree mortality through time. We used two-dimensional spatial analysis tools with data gathered in point-centered-quarter format in 2001 and 2004 to quantify the population density of the disease through time; to examine the spatial pattern of tree mortality across scales through time; and to examine the spatial co-occurrence of disease symptoms with crown mortality through time. Early in the study period dead trees were strongly clustered at smaller scales (*300 m) and after three years this clustering was less pronounced. Bleeding on trees occurred in clusters away from dead trees, particularly in 2004, likely indicating a new cohort of infected trees. The presence of H. thouarsianum was strongly related to overstory mortality through time. Beetle-infested trees cooccurred with mortality in 2001. By 2004, they occurred throughout the forest, and were less strongly correlated with overstory tree mortality, suggesting a future peak of tree mortality.

The fifth oak symposium was designed to provide a forum for current research and outstanding case studies on oak woodland conservation and sustainability in California. The previous conferences-held in 1979, 1986, 1990, and 1996-serve as rich sources of information about a wide range of subjects on oak ecology, management, uses, planning and conservation. This conference is aimed at natural resource managers, researchers, policy makers, and public and private interest groups. Seventy-two papers are presented in the proceedings. Topics covered include: grazing relations, soil relations, Garry oak conservation, oak regeneration and restoration, fire relations, wildlife relations, urban forestry, oak woodland policy, genetic factors, monitoring, ecology, and a special session on "Sudden Oak Death."