Treesearch

A study was begun in the winter of 2000-2001 and continued through the winter of 2001-2002 to examine air quality at the Green Rock snowmobile staging area at 2,985 m elevation in the Snowy Range of Wyoming. The study was designed to evaluate the effects of winter recreation snowmobile activity on air quality at this high elevation site by measuring levels of nitrogen oxides (NOx, NO), carbon monoxide (CO), ozone (O3) and particulate matter (PM10 mass). Snowmobile numbers were higher weekends than weekdays, but numbers were difficult to quantify with an infrared sensor. Nitrogen oxides and...

A new method is considered that can be used for inverting data obtained from a combined elastic-inelastic lidar or a high spectral resolution lidar operating in a one-directional mode, or an elastic lidar operating in a multiangle mode. The particulate extinction coefficient is retrieved from the simultaneously measured profiles of the particulate backscatter coefficient and the particulate optical depth. The stepwise profile of the column-integrated lidar ratio is found that provides best matching of the initial (inverted) profile of the optical depth to that obtained by the inversion of...

An improved measurement methodology and a data-processing technique for multiangle data obtained with an elastic scanning lidar in clear atmospheres are introduced. Azimuthal and slope scans are combined to reduce the atmospheric heterogeneity. Vertical profiles of optical depth and intercept (proportional to the logarithm of the backscatter coefficient) are determined. The purpose of this approach is to identify and remove data points that distort the regression analysis results in order to improve the accuracy of the retrieved optical depth and of the intercept. In addition, the influence...

Combustion of wildland fuels represents a major source of particulate matter (PM) and light-absorbing elemental carbon (EC) on a national and global scale, but the emission factors and source profiles have not been well characterized with respect to different fuels and combustion phases. These uncertainties limit the accuracy of current emission inventories, smoke forecasts, and source apportionments. This study investigates the evolution of gaseous and particulate emission and combustion efficiency by burning wildland fuels in a laboratory combustion facility.

Reducing the risk of losses from wildfires that threaten homes and communities is a growing priority in Canada. To reduce risk, “FireSmart®” standards have been adopted nationwide for managing forest fuel. However, these standards largely disregard interests of wildlife and conservation of wildlife habitat – thus raising concerns among residents and other stakeholders. To be acceptable, fuel treatments in wildland/urban interface areas of Jasper National Park, Alberta, required that potential environmental impacts and the requirements of wildlife also be carefully considered. A research...

The 24- to 72-hour fire-weather predictions for different regions of the United States are now readily available from the regional Fire Consortia for Advanced Modeling of Meteorology and Smoke (FCAMMS) that were established as part of the U.S. National Fire Plan. These predictions are based on daily real-time MM5 model simulations of atmospheric conditions and fire-weather indices over specific modeling domains. Included in the suite of fire-weather indices provided by the FCAMMS is the well-known Haines Index (HI), an operational “mesoscale-type” index that characterizes the atmospheric...

The use of native plants for rehabilitation after wildfires and restoration of disturbed wildlands is being encouraged by various BLM programs, initiatives, and policies. Examples include the 2001-2006 Interior Appropriations Bills, the Great Basin Restoration Initiative, Departmental guidance (DOI Emergency Stabilization and Rehabilitation Manual), Executive Order 13112 (Invasive Species - 2/99) and the BLM’s Standards for Rangeland Health. The 2007 USDI Healthy Lands Initiative calls for landscape-scale restoration to reduce the spread of invasive species and re-establish native communities.

Currently, no methods of predicting microscale, terrain influenced winds are available to fire managers. This study evaluated three methods of providing surface wind information to fire growth models. One was simply a uniform wind speed and direction, a method that has been traditionally used, and the other two types were based on numerical models used in the pollutant dispersion and wind power generation fields. The models were a commercial computational fluid dynamics (CFD) model and a mass-consistent model.

The objective of this study was to determine the relationship, or lack thereof, between growth and diversity of tree species and size in conifer stands of western North America. Growth was measured by net basal area growth and its components: survivor growth, recruitment, and mortality. The analysis used inventory data from permanent plots in the Douglas-fir/western hemlock forest type in Oregon and Washington, and in the mixed-conifer forest type in California. The methods consisted of generalized least square regression with spatial autocorrelation, controlling for the effect of other...

The importance of efficaciously assessing the risk for introduction and establishment of pest species is an increasingly important ecological and economic issue. Evaluation of climate is fundamental to determining the potential success of an introduced or invasive insect pest. However, evaluating climatic suitability poses substantial difficulties; climate can be measured and assessed in a bewildering array of ways. Some physiological filter, in essence a lens that focuses climate through the requirements and constraints of a potential pest introduction, is required. Difficulties in...