Treesearch

In 2002, a team of United States Department of Agriculture-Forest Service (USDA-FS) scientists developed a preliminary risk map to serve as the foundation for an efficient, cost effective sample design for the national sudden oak death detection survey. At the time, a need to initiate rapid detection in the face of limited information on Phytophthora ramorum necessitated a simple spatial intersection of factors traditionally used in risk mapping: (1) distribution of hosts known or likely to be susceptible to the pathogen, (2) climatic conditions adequate for survival and propagation of the...

The Million Trees LA initiative intends to chart a course for sustainable growth through planting and stewardship of trees. The purpose of this study was to measure Los Angeles's existing tree canopy cover (TCC), determine if space exists for 1 million additional trees, and estimate future benefits from the planting. High resolution QuickBird remote sensing data, aerial photographs, and geographic information systems were used to classify land cover types, measure TCC, and identify potential tree planting sites. Benefits were forecast for planting of 1 million trees between 2006 and 2010,...

With the expansion of global trade, problems with invasive alien pests have also grown. In order to reduce the international movement of plant pests and protect valuable plant resources, national plant protection regulations and international standards continue to be developed. Science is critical to the development of effective national and international plant protection regulations aimed at reducing the spread of plant pests. There is an increasing recognition that such regulations be ?science-based? as identified in the World Trade Organization Sanitary and Phytosanitary Measures...

The current rules for plants for planting are being revised. The United States Department of Agriculture-Animal and Plant Health Inspection Service (USDA-APHIS) has already provided several opportunities for public input into the new rules, and more opportunities will be coming soon. Considering the importance most plant health scientists attach to this issue, it is surprising how few people contribute comments. It is as easy as sending an email, once you sign up for notices. The proposed changes to the rules are outlined in this paper, with suggestions for research needs to inform the...

The Big Sur area is one of the most ecologically diverse regions in California. Land preservation efforts are well established in Big Sur, including numerous preserves, state parks and the Los Padres National Forest. However, there are still many conservation threats that cut across these areas including exotic species (plants, animals, and pathogens) and alterations of key natural processes such as a fire. Big Sur provides an ideal environment to address questions on the ecological consequences of Phytophthora ramorum due to the extensiveness of the forests, the relatively high impact of...

We modeled Phytophthora ramorum infection using the North Carolina State University- Animal and Plant Health Inspection Service Plant Pest Forecasting System (NAPPFAST) for the conterminous United States. Our infection model is based on a temperature-moisture response function. The model parameters were: leaf wetness, minimum temperature, optimum temperature and maximum temperature over a specified number of accumulated days. The NAPPFAST weather database, which involves approximately 2,000 weather stations across North America, was used to generate a spatially interpolated climate match...

Economic and environmental impacts of Phytophthora ramorum in Europe were evaluated within the European Union framework 6 project on ?Risk Analysis for P. ramorum a pathogen threat to Europe? (RAPRA). Impact assessment was conducted according to three different scenarios: 1. ?Nursery System? - describes losses occurring in nurseries where special growing conditions and trade with plant material influence spread and dimension of the disease, 2. ?Northern European Tree Host System? - based on observations in the United Kingdom, the Netherlands and Germany where infections of trees (beech,...

Plant pathogens of the oomycete lineage share common susceptibilities to many biotic and abiotic stresses. We are investigating the potential of antagonistic bacteria, isothiocyanates, and mycophagous amoebae to control diseases caused by Phytophthora spp., including the etiologic agent of sudden oak death, Phytophthora ramorum (Rizzo and others 2005), and Pythium spp., which cause seedling root rotting diseases across the plant kingdom (Hendrix and Campbell 1973). Antagonistic bacteria. Inoculation of plant growth media with surfactant-producing bacteria is an established method for...

Human land-use practices have resulted in dramatic alterations of forest ecosystems worldwide. By modifying transmission pathways and habitat structure, land use changes are being increasingly implicated in the emergence of infectious plant disease. In this research, we examined the effects of human-related land-cover change on the establishment of the invasive plant pathogen Phytophthora ramorum, causal agent of the forest disease sudden oak death. We hypothesized oak woodlands in coastal California have increased in density and expanded into grassland and shrubland areas over the last...

Since the first finding of Phytophthora ramorum in the U.K. (on Viburnum tinus, 2002), the pathogen has been reported throughout the country on a variety of susceptible species both in the horticultural sector and in woodlands and historic gardens. The nursery network may have properties which affect the epidemic threshold for spread of the pathogen. Here, as part of ongoing modeling studies, we provide an analysis of the database of positive P. ramorum records in England and Wales (2003 to 2005), both in terms of affected plant genus and country of origin. The majority of positive...