Treesearch

Armillaria (Fr.) Staude is a widely distributed fungal genus comprising approximately 40 species (Volk and Burdsall 1995) that display diverse ecological behaviors ranging from beneficial saprobe to virulent pathogen. Armillaria solidipes (formerly A. ostoyae; Burdsall and Volk 2008; pending vote to conserve A. ostoyae; Redhead et al. 2011), one of the causal agents of Armillaria root disease, is a virulent primary pathogen with a broad host range in northern temperate latitudes (Kile et al. 1991). This fungal pathogen attacks sapwood as mycelial fans under the bark, and grows between...

The U.S. Department of Agriculture, Forest Service (USFS) has, in recent years, increasingly emphasized the importance of safety to its employees, but wildfire management remains a risky endeavor. While wildfire management decisions affecting safety and exposure of firefighters to the wildland fire environment may be aided by decision support tools such the Wildfire Decision Support System, use of such tools may be influenced by the way information is presented and by manager responses to risk. A recent survey of wildfire managers conducted by the USFS Rocky Mountain Research Station and...

Time-resolved irradiance and convective heating and cooling of fast-response thermopile sensors were measured in 13 natural and prescribed wildland fires under a variety of fuel and ambient conditions. It was shown that a sensor exposed to the fire environment was subject to rapid fluctuations of convective transfer whereas irradiance measured by a windowed sensor was much less variable in time, increasing nearly monotonically with the approach of the flame front and largely declining with its passage. Irradiance beneath two crown fires peaked at 200 and 300kWm-2, peak irradiance associated...

Time-resolved radiative and convective heating measurements were collected on a prescribed burn in coniferous fuels at a sampling frequency of 500 Hz. Evaluation of the data in the time and frequency domain indicate that this sampling rate was sufficient to capture the temporal fluctuations of radiative and convective heating. The convective heating signal contained significantly larger fluctuations in magnitude and frequency than did the radiative heating signal. The data were artificially down-sampled to 100, 50, 10, 5 and 1 Hz to explore the effect of sampling rate on peak heat fluxes,...

In Canadian boreal forests, wildfire is the predominant agent of natural disturbance often with millions of hectares burning annually. In addition to fire, nearly one quarter of Canada's boreal forest is also managed for industrial wood production. Post-fire logging (or salvage harvesting) is increasingly used to minimize economic losses from fire, notwithstanding that the ecological impacts of successive disturbance events remain poorly understood. Improved monitoring and management of post-fire environments will require new information regarding the location and timing of past operations....

Random Forests is frequently used to model species distributions over large geographic areas. Complications arise when data used to train the models have been collected in stratified designs that involve different sampling intensity per stratum. The modeling process is further complicated if some of the target species are relatively rare on the landscape leading to an unbalanced number of presences and absences in the training data. We explored means to accommodate unequal sampling intensity across strata as well as the unbalanced species prevalence in Random Forest models for tree and...

More diverse sources of energy are needed for countries to progress toward energy independence and to meet future food production needs. The US Task Force on Strategic Unconventional Fuels concluded that to achieve this objective it is essential to develop a domestic unconventional fuels industry. Rangelands, which cover 50% to 70% of the earth's terrestrial surface and dominate much of the western half of the United States, represent a major source of alternative energy resources. A framework to systematically identify biophysical-socioeconomic links that influence the delivery of...

Fusarium commune can cause damping-off and root rot of conifer seedlings in forest nurseries. The pathogen is only reported in Oregon, Idaho, and Washington within United States. Fusarium isolates were collected from midwestern and western United States to determine occurrence of this pathogen. DNA sequences of mitochondrial small subunit gene were used to identify F. commune. In addition to the aforementioned states, F. commune was found from nurseries in Nevada, Montana, Nebraska, and Michigan, USA.

Demand for forest biomass for bioenergy production and other uses is expected to increase to four times the current level in the next one to five years. The search for alternative energy sources, including forest bioenergy, increases pressure on the productive capacity of our western forestlands. The questions are: Can forest soils in the western U.S. support more intensive timber harvesting for both traditional uses and emerging bioenergy markets? Are biomass harvesting for bioenergy and sustainable soil productivity compatible? The answers are "yes!"

Native grass, forb, and shrub seed is needed to restore rangelands of the U.S. Intermountain West. Fernleaf biscuitroot [Lomatium dissectum (Nutt.) Mathias & Constance] is a desirable component of rangelands. Commercial seed production is necessary to provide the quantity and quality of seed needed for rangeland restoration and reclamation efforts. Fernleaf biscuitroot has been used for hundreds if not thousands of years in the western United States as a source of food and medicine. Knowledge about fernleaf biscuitroot is confined to ethnobotanical reports, evaluation of some of its...