Treesearch

Phellinus sulphurascens (previously the Douglas-fir form of Phellinus weirii) is an important native pathogen causing laminated root rot in forests of western North America. Visual crown symptoms, or attacks by bark or ambrosia beetles appear only during advanced stages of the disease with extensive infection in the lower bole. Ethanol synthesis is one of many physiological responses in tree tissues stressed by pathogens. Ethanol, acetone and other volatiles from root tissues of healthy and diseased trees were analyzed using headspace gas chromatography. Xylem and phloem from 20 diseased...

Atmospheric nitrogen (N) deposition has been shown to decrease plant species richness along regional deposition gradients in Europe and in experimental manipulations. However, the general response of species richness to N deposition across different vegetation types, soil conditions, and climates remains largely unknown even though responses may be contingent on these environmental factors. We assessed the effect of N deposition on herbaceous richness for 15,136 forest, woodland, shrubland, and grassland sites across the continental United States, to address how edaphic and climatic...

Mosses accumulate pollutants from the atmosphere and can serve as an inexpensive screening tool for mapping air quality and guiding the placement of monitoring instruments. We measured 22 elements using 346 moss samples collected across Portland, Oregon, in December 2013. Our objectives were to develop citywide maps showing concentrations of each element in moss and identify potential air pollution “hotspots.” We used simple dot maps, histograms, and summary statistics to describe the distribution of each element. Fifteen metals had highly right-skewed distributions, indicating high metal...

Higher global temperatures are changing ecosystems in the Arctic. They are becoming greener as the climate and land become more hospitable to taller vegetation. Scientists predict that woody vegetation in the Arctic will increase by more than 50 percent, and half of all vegetated areas will shift to types more suited to the higher temperatures and changing physical conditions. The implications for wildlife and people living in the Arctic are striking and hinge on rapid changes affecting ecosystems and habitats.Bruce Marcot, a research wildlife biologist with the Pacific Northwest Research...

A conservation goal of the Northwest Forest Plan (NWFP) is to stabilize and increase marbled murrelet (Brachyramphus marmoratus) populations by maintaining and increasing nesting habitat. We monitored murrelet populations offshore of the NWFP area from 2000 to 2013 to estimate population size and trend at several spatial scales. At the conservationzone scale, 2013 population estimates ranged from 71 birds in Conservation Zone 5 (San Francisco Bay north to Shelter Cove, California) to 7,880 in Conservation Zone 3 (Coos Bay, Oregon north to the Columbia River). The 2013 estimate for the...

Communicating emissions impacts to the public can sometimes be difficult because quantitatively conveying smoke concentrations is complicated. Regulators and land managers often refer to particulate-matter concentrations in micrograms per cubic meter, but this may not be intuitive or meaningful to everyone. The primary purpose of this guide is to serve as a tool for communicating potential particulate matter (PM2.5) levels during wildfire events using visual representation. Examples of visibility impairment under various levels of smoke concentration and humidity have been modeled using...

This report highlights significant research findings and accomplishments of the Pacific Northwest Research Station during fiscal year 2015.

A wood-based energy project in Craig, Alaska, to heat the community's aquatic center and two of its schools was the first such installation in Alaska to convert from fossil fuels to a renewable energy source. Initial interest in the project started in 2004. The system came online in April 2008. This report provides an overview of the new heating system's history, including a review of fuel costs during the study period; background information about the climate and wood resources in the region; initial conception, design, tendering, and construction; and a 5-year summary of operating...

This special issue of Fire Ecology is focused on the fire ecology of eastern USA oak (Quercus L.) forests, woodlands, and savannas. The papers were presented as part of the Fifth Fire in Eastern Oak Forests Conference in Tuscaloosa, Alabama, USA, in 2015. The topic of fire in eastern oak ecosystems is one that has received insufficient interest from the broader fire ecology com- munity. Specific papers in this issue address the historical role of fire in the region, the response and adaptations of plant and animal species to fire and fuels treatments, and the future of these important...

We investigated the influence of landscape factors on the distribution and life stage stability of coastal tree species near the northern limit of their ranges. Using data from 1465 forest inventory plots, we estimated probability of occurrence and basal area of six common conifer species across three broad latitudinal regions of coastal Alaska. By also comparing models across life stages of each species (seedlings, saplings, mature trees, and dead trees), we explored trends in population stability at this leading edge of climate change. Elevation had a stronger influence on the probability...