Treesearch

Industrial nitrogen (N) emissions in the Athabasca oil sands region (AOSR), Alberta, Canada, affect nitrate (NO3) and ammonium (NH4) deposition rates in close vicinity of industrial emitters. NO3-N and NH4-N open field and throughfall deposition rates were determined at various sites between 3 km and 113 km distance to the main oil sand operations between May 2008 and May 2009. NO3 and NH4 were analyzed for δ15N-NO3, δ18O-NO3, Δ17O-NO3 and δ15N-NH4. Marked differences in the δ18O and Δ17O values between industrial emissions and background deposition allowed for the estimation of minimum...

Wet,dry and throughfall deposition of N and S were measured for 2 years in three national parks in Washington State:Olympic,Mount Rainier,and North Cascades.Throughfall was measured using ion exchange resin (IER) collectors. A major objective of the study was to evaluate the effectiveness of IER throughfall measurements for monitoring deposition inputs,including cloudwater deposition, to forest stands in national parks and other protected areas. Wet deposition (0.9–2.0kgN-1ha-1yr)and throughfall (0.5–1.2kgN-1ha-1yr) deposition of inorganic N in the three parks were relatively low. Wet...

For several decades, southern California experienced the worst ozone pollution ever reported. Peak ozone concentrations have, however, declined steadily since 1980. In this study, the structural injuries underlying ozone symptoms in needles of ponderosa pine (Pinus ponderosa Dougl. ex Laws.) collected in summer 2006 from one of the most polluted sites in the San Bernardino Mountains were investigated using serial sections examined by light and electron microscopy. Ozone-specific light-green diffuse mottling was observed in the currentyear needles, whereas older foliage showed brownish...

A total of 208 participants from 78 organizations in 19 countries gathered at the Waikoloa Beach Marriott on the Big Island of Hawaii on September 11-16, 2011 for the XIII International Symposium on Biological Control of Weeds. Following a reception on the first evening, Symposium co-chairs Tracy Johnson and Pat Conant formally welcomed the attendees on the morning of September 12, and introduced Bill Steiner, Dean of the College of Agriculture, Forestry and Natural Resource Management, University of Hawaii at Hilo, who provided opening remarks on future directions of invasive species...

For applied mathematicians forest fire models refer mainly to a non-linear dynamic system often used to simulate spread of fire. For forest managers forest fire models may pertain to any of the three phases of fire management: prefire planning (fire risk models), fire suppression (fire behavior models), and postfire evaluation (fire effects and economic models). In this context forest fire models may be statistical, rule-based, process-based or a combination of all three.

Encouraging the public to take action (e.g., creating defensible space) that can reduce the likelihood of wildfire damage and decrease the likelihood of injury is a common approach to increasing wildfire safety and damage mitigation. This study was designed to improve our understanding of both individual and community actions that homeowners currently do or might take to protect their home or property, and the barriers that impede homeowners from completing firewise treatments to their home or property.

This paper examines the political construction of a policy instrument for matching particular institutional, biophysical and cultural context conditions in a social–ecological system, using the case of conservation banking in California as an example. The guiding research question is: How is policy design negotiated between various actors on its way from early formulation of ideas and principles to an accepted policy solution on a state or national level? The underlying assumption is that in order for a policy instrument to be implemented, it has to be adjusted to various context conditions...

We compared the ability of several classification and regression algorithms to predict forest stand structure metrics and standard surface fuel models. Our study area spans a dense, topographically complex Sierra Nevada mixed-conifer forest. We used clustering, regression trees, and support vector machine algorithms to analyze high density (average 9 pulses/m2), discrete return, small-footprint lidar data, along with multispectral imagery. Stand structure metric predictions generally decreased with increased canopy penetration. While the general fuel types were predicted accurately,...

The impacts of wildfires on tourism have largely been examined with emphasis on economic losses and recovery strategies. Given the limited research from a demand perspective, this study examined tourist risk perceptions and reactionary behaviors toward wildfires in Florida. Data (N ¼ 771) was collected among a U.S. sample of non-resident overnight leisure travelers that had visited Florida previously. Three clusters were identified with a larger segment in the middle (Conscious Travelers) of the curve, and higher risk (Cautious Travelers) and lower risk (Courageous Travelers) segments at...

Various forms of Pinus ponderosa Douglas ex C. Lawson are found from British Columbia southward and eastward through 16 states and, perhaps, into Mexico. The status of many names previously associated with this species, but excluded here, has been clarified. Accumulated evidence based on variation in morphology and xylem monoterpenes, partial genetic barriers to crossing, and allozyme differences leads to recognition of five subspecies: Pinus ponderosa subsp. ponderosa, Columbia ponderosa pine, southward from southern British Columbia, east of the Cascade Range in Washington, Oregon, and...