Treesearch

Profiles are provided for 5 forest Phytopthora species: P. kernoviae, P. pinifolia, P.alni, P. cinnamomi, P.katsurae. Also presented are a "Host and Habitat Index for Phytophthora Species in Oregon" and "Histopathological Investigations of the Infection Process and Propagule Development of Phytophthora ramorum on Rhododendron Leaves".

Invasive species risk maps provide broad guidance on where to allocate resources for pest monitoring and regulation, but they often present individual risk components (such as climatic suitability, host abundance, or introduction potential) as independent entities. These independent risk components are integrated using various multicriteria analysis techniques that typically require prior knowledge of the risk components’ importance. Such information is often nonexistent for many invasive pests. This study proposes a new approach for building integrated risk maps using the principle of a...

Economic globalization depends on the movement of people and goods between countries. As these exchanges increase, so does the potential for translocation of harmful pests, weeds, and pathogens capable of impacting our crops, livestock and natural resources (Hulme 2009), with concomitant impacts on global food security (Cook et al. 2011).

This study assesses the survival of Phytophthora ramorum in the root ball of Rhododendron container plants as well as in different rootless forest substrates and a horticultural potting medium. Following inoculation of the root balls, the aboveground plant parts stayed symptomless, whilst the pathogen could be recovered with a novel non-destructive baiting assay from the root balls until at least 8 months post-inoculation. Plating of surface-sterilized roots and direct microscopic analysis confirmed the presence of P. ramorum in the roots. Phytophthora ramorum could also be baited from the...

Our objectives were to establish inoculum density relationships between P. ramorum and selected hosts using detached leaf and whole-plant inoculations. Young plants and detached leaves of Quercus prinus (Chestnut oak), Q. rubra (Northern red oak), Acer rubrum (red maple), Kalmia latifolia (mountain laurel) and Rhododendron ‘Cunningham’s White’ were dipinoculated with varying numbers of P. ramorum sporangia, and the total number of diseased and healthy leaves recorded following incubation at 20ºC and 100% relative humidity. Calibration threshold estimates for obtaining 50%...

N2-fixing trees can affect stream water quality. This has been documented in temperate streams, but not in tropical ones, even though N2-fixing trees are prevalent in the tropics. We investigated the effects of the introduced, invasive tree, Falcataria moluccana albiziaon water quality of Hawaiian streams. Nutrient concentrations were measured in reaches above and below F. moluccana-dominated riparian zones of four streams over 14 mo, and benthic algal nutrient limitation was examined in one stream. NO3-+NO2- concentrations were up to 600 percent higher in reaches below F. moluccana stands...

This publication provides an overview of forest resource attributes for Ohio based on an annual inventory conducted by the Forest Inventory and Analysis (FIA) program at the Northern Research Station of the U.S. Forest Service. These estimates, along with web-posted core tables, will be updated annually. For more information please refer to page 4 of this report.

The forest products industry accounts for approximately 6% of total U.S. manufacturing output; nanotechnology could play an increasing role. As with any emerging technology, cellulose nanomaterials may become commercially available in a range of products before society obtains sufficient knowledge of the risk they pose to workers, consumers, and the environment. In partnership with the Forest Products Laboratory, the National Institute for Occupational Safety and Health conducted an exposure characterization study of the production of cellulose nanocrystals (CNC) that had been tagged with...

A new species, Phytophthora pluvialis is described. P. pluvialis has been recovered from streams, soil and canopy drip in the mixed tanoak-Douglas-fir forest in Curry County, Oregon, and in two additional streams in other areas of western Oregon. It has been found only rarely in association with twig and stem cankers on tanoak but not with any other plant host. The earliest isolate of P. pluvialis was from soil in 2002. P. pluvialis is classified in ITS Clade 3.

Tanoaks, Notholithocarpus densiflorus (Hook. & Arn.) Manos, Cannon & S. H. Oh, are being killed by sudden oak death, caused by the pathogen Phytophthora ramorum Werres, de Cock & Man in't Veld. However, very little is known about the basic ecology of the species. Here we investigate the pollination ecology of tanoaks using insect-visitor observations along with a pollinator-exclusion study. Insect-visitor observations were conducted by citizen-scientist volunteers at three different sites in the Midpeninsula Regional Open Space District lands in the Coast Range of California in 2009....