Treesearch

For environmental problems such as climate change, uncertainty about future conditions makes it difficult to know what the goal of mitigation efforts should be, and inequality among the affected parties makes it hard for them to know how much they each should do toward reaching the goal. We examine the effects of scientific uncertainty and wealth inequality in experiments where subjects decide how much to contribute toward reducing a common threat. We also explore how the framing of uncertainty affects collective action. Our results suggest that uncertainty lowers contributions, but...

The concepts of animal units, animal unit months, and animal unit equivalents have long been used as standards for range management planning, estimating stocking rates, reporting actual use, assessing grazing fees, ranch appraisal, and other purposes. Increasing size of cattle on rangelands has led some to suggest that the definition of animal units and animal unit months requires revision. Range managers need to understand these concepts and arbitrarily changing them would lead to confusion. The Rangeland Assessment and Monitoring Committee reviewed this issue and concluded that the...

Microsatellite analysis initially identified genetic variations within the NA1 clonal lineage of Phytophthora ramorum; however, in Washington nurseries, the genetic population of P. ramorum has shifted and is now dominated by two other lineages, NA2 and EU1. In this study, recently identified markers that are more variable, and therefore more informative for the EU1 lineage, were used to reveal genetic diversity within the Washington P. ramorum EU1 population. Data from genotyping of DNA samples provided by the Washington State Department of Agriculture (WSDA) was combined with new...

A Phytophthora cactorum-infected nursery crop of Ceanothus thyrsiflorus was used to evaluate three Phytophthora monitoring methods. The Phytophthora detection level of three non-destructive sampling methods was quantified and compared to the detection level of destructive sampling. Non-destructive methods were (a) composite soil/root samples, pear-baited, (b) effluent samples, pear-baited, and (c) Agdia ImmunoStrip tests run on root samples. Time and expense of each method were also tracked. The baited soil/root sample method was the least labor intensive and most cost-effective method to...

Horticultural nurseries are under increasing pressure to reduce, remediate, and recycle irrigation water. A major constraint for reusing irrigation water is contamination by waterborne plant pathogenic Phytophthora and Pythium species. Current research is focused on helping plant nurseries monitor oomycete pathogens in their irrigation water to determine the need for water treatment, evaluate effectiveness of treatment options, and enable selection of cost-effective ways to disinfest water. A sensitive method to identify waterborne oomycetes present at low concentrations was needed. A...

Sudden Oak Death (SOD) is the common name for a disease caused by Phytophthora ramorum (oomycetes), an invasive plant pathogen of regulatory concern. The nursery, timber, forest specialty product, and Christmas tree industries in Washington are at risk because of the spread of P. ramorum within nurseries and from nurseries into waterways and the landscape. This study was initiated in 2010 in order to monitor for early detection of P. ramorum in western Washington streams and ponds. Since P. ramorum, to date, has been documented to be established in only a few WA streams, this survey...

The spread of Phytophthora ramorum from infested areas in nurseries and landscape sites is commonly associated with the movement of inoculum in water or from the movement of contaminated soils. It has been shown that P. ramorum can survive asymptomatically on roots of containerized plants and in potting media. The development and implementation of cost effective and environmentally acceptable best management practices (BMPs) to limit the spread of P. ramorum has been identified as a high priority need by the nursery and forestry industries as well as state and federal regulatory agencies.

Phosphomolybdic acid (PMo12) was used as an electron mediator and proton carrier to mediate biomass pretreatment for ethanol production and electricity generation from wheat straw. In the pretreatment, lignin was oxidized anaerobically by PMo12 with solubilization of a fraction of hemicelluloses, and the PMo12 was simultaneously reduced. In an external liquid flow cell, the reduced PMo12 was re-oxidized with generation of electricity. The effects of several factors on pretreatment were investigated for optimizing the conditions. Enzymatic conversion of cellulose and xylan were about 80%...

Genetic diversity provides the essential basis for the adaptation and resilience of tree species to environmental stress and change. The genetic conservation of tree species is an urgent global necessity as forest conversion and fragmentation continue apace, damaging insects and pathogens are transported between continents, and climate change alters local habitat suitability. Effective and efficient genetic conservation of tree species presents a substantial challenge because of the lack of basic information about many species, inadequate resources, and a historical lack of coordination...

Phytophthora ramorum continues to cause extensive mortality of tanoaks in southwestern Oregon. Effective management strategies have been developed based on our current understanding of the pathogen’s epidemiology. Local dispersal can occur either by canopy throughfall (“top-down”) or a ground splash (“bottom-up”) pathway. Although the “top-down” aspect of the disease cycle is well understood, the importance of infested soil and leaf litter as contributing factors to the spread of disease remains unclear. To elucidate the epidemiological importance of these “bottom-up” sources of inoculum,...