Research and Publications
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Fuel treatments are widely used to alter fuels in forested ecosystems to mitigate wildfire behavior and effects. However, few studies have examined long-term ecological effects of interacting fuel treatments (commercial harvests, pre-commercial thinnings, pile and burning, and prescribed fire) and wildfire. Using annually fitted Landsat satellite-derived Normalized Burn Ratio (NBR) curves and paired pre-fire treated and untreated field sites, we tested changes in the differenced NBR (dNBR) and years since treatment as predictors of biophysical attributes one and nine years after the 2007 Egley Fire Complex in Oregon, USA. We also assessed short- and long-term fuel treatment impacts on field-measured attributes one and nine years post fire.
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We argue that prescribed fire science requires a fundamentally different approach to connecting related disciplines of physical, natural, and social sciences. We also posit that research aimed at questions relevant to prescribed fire will improve overall wildland fire science and stimulate the development of useful knowledge about managed wildfires. Because prescribed fires are increasingly promoted and applied for wildfire management and are intentionally ignited to meet policy and land manager objectives, a broader research agenda incorporating the unique features of prescribed fire is needed. We highlight the primary differences between prescribed fire science and wildfire science in the study of fuels, fire behavior, fire weather, fire effects, and fire social science. Wildfires managed for resource benefits (“managed wildfires”) offer a bridge for linking these science frameworks. A recognition of the unique science needs related to prescribed fire will be key to addressing the global challenge of managing wildland fire for long-term sustainability of natural resources.
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This longer-term study essentially shows that native seed mixes do well in suppressing cheatgrass in the Great Basin, even when compared to familiar conventional mixes that include the highly competitive nonnative crested and Siberian wheatgrass. The conventional seed mixes lived up to their reputation and were effective at keeping cheatgrass cover below 2 percent, but the native seed mixes were not far behind, with cheatgrass cover of 3 percent to 6 percent–in contrast to unseeded control treatments where cheatgrass cover reached 9 percent to 15 percent. And using native seed mixes may not be cost-prohibitive anymore—the scientists found that the price of native species seed has come down over the years to be much closer to that of introduced mixes.
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Field and laboratory emission factors (EFs) of wildland fire emissions for 276 known air pollutants sampled across Canada and the US were compiled. An online database, the Smoke Emissions Repository Application (SERA), was created to enable analysis and summaries of existing EFs to be used in smoke management and emissions inventories. We evaluated how EFs of select pollutants (CO, CO2, CH4, NOx, total particulate matter (PM), PM2.5 and SO2) are influenced by combustion phase, burn type and fuel type. Of the 12 533 records in the database, over a third (n = 5637) are represented by 23 air pollutants, most designated as US Environmental Protection Agency criteria air pollutants, greenhouse gases, hazardous air pollutants or known air toxins. Among all pollutants in the database, including the most common pollutants PM, CO, CO2 and CH4, records are unevenly distributed with a bias towards flaming combustion, prescribed burning and laboratory measurements. Across all EFs, records are most common for south-eastern and western conifer forests and western shrubland types. Based on identified data gaps, we offer recommendations for future studies, including targeting underrepresented air pollutants, smouldering combustion phases and improved source characterisation of wildland fire emissions.
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This study evaluated drivers of fire severity and fuel treatment effectiveness in the 2014 Carlton Complex, a record‐setting complex of wildfires in north‐central Washington State. All treatment areas burned with higher proportions of moderate and high severity fire during early fire progressions, but thin and underburn, underburn only, and past wildfires were more effective than thin‐only and thin and pile burn treatments. Treatment units had much greater percentages of unburned and low severity area in later progressions that burned under milder fire weather conditions, and differences between treatments were less pronounced. Our results provide evidence that strategic placement of fuels reduction treatments can effectively reduce localized fire spread and severity even under severe fire weather. During wind‐driven fire spread progressions, fuel treatments that were located on leeward slopes tended to have lower fire severity than treatments located on windward slopes. As fire and fuels managers evaluate options for increasing landscape resilience to future climate change and wildfires, strategic placement of fuel treatments may be guided by retrospective studies of past large wildfire events.
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Springs serve an ecologically important role as perennial water sources, essential habitat for native species, and support for stream flow. Spring developments on rangelands provide water to livestock and wildlife. Thoughtful design of sustainable developments will supply water to livestock and wildlife while maintaining the intrinsic ecological functions and values of springs. This guide addresses spring development project planning as well as long-term sustainable management of springs. The objectives of spring development design are (1) to retain hydrologic conditions in the developed spring habitat that are similar to undeveloped reference habitats and (2) to create a system that is easy to install and maintain. Report presents two gravity-flow development designs that incorporate flow-splitting devices to regulate environmental flows and levels and to work in a wide range of hydrologic conditions.
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This study assessed plant community succession following prescribed fire on ungrazed Wyoming big sagebrush steppe, eastern Oregon. Herbaceous yield, vegetation canopy cover and density were compared between treatments after fire (2003–18). Herbaceous yield in the Burn treatment was about double the control for most of the study period. Prior to fire, native perennials comprised 90–95% of herbaceous yield. After fire, native perennials represented 78% (range 67–93%) and exotic annuals 22% (range 7–33%) of total yield. Exotic annuals increased after fire and responded in two stages. In the first 8 years after fire, desert alyssum dominated the annual plant composition. In the last half of the study, cheatgrass co-dominated the annual component with alyssum. Sagebrush recovery was slow and we estimated sagebrush cover would return to pre-burn levels, at the earliest, in 115 years. Burning Wyoming big sagebrush steppe would be detrimental to sagebrush-obligate wildlife for an extended time period, because of lost cover and structure provided by sagebrush. The additional forage provided on burned areas may give livestock manager’s greater flexibility to rest or defer unburned habitat for wildlife species of critical concern.
Cheatgrass Challenge webpage.
The Bureau of Land Management (BLM) and Natural Resources Conservation Service (NRCS) in Idaho and Wyoming have teamed up with each other along with partners in their respective states to address cheatgrass proliferation in the West. The Cheatgrass Challenge is a call to arms for agricultural producers, federal and state agencies, educational institutions and non-profit organizations.
As the Challenge develops, the webpage will be updated with additional information and resources, so check back regularly for updates.
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Study results suggest that lateral root functioning in Artemisia tridentata is associated with intraspecific identity and ploidy level. Subspecies adapted to habitats with deep soils generally had a smaller horizontal reach, and polyploid cytotypes were associated with greater water uptake compared to their diploid variants. Plant crown volume was a weak predictor of water uptake, and that neighborhood crowding had no discernable effect on water uptake. Intraspecific variation in lateral root functioning can lead to differential patterns of resource acquisition, an essential process in arid ecosystems in the contexts of changing climate and seasonal patterns of precipitation. Altogether, we found that lateral root development and activity is more strongly related to genetic variability within A. tridentata than to plant size. This study highlights how intraspecific variation in life strategies is linked to mechanisms of resource acquisition.
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This study reports an automated method of mapping rangeland fractional component cover over a large portion of the northern Great Basin, from 1986 to 2016 using a dense Landsat imagery time series. Over the 30‐yr period, shrub cover declined and bare ground increased. While few pixels had >10% cover change, a large majority had at least some change. All fractional components had significant spatial relationships with water year precipitation (WYPRCP), maximum temperature (WYTMAX), and minimum temperature (WYTMIN) in all years. Shrub and sagebrush cover in particular respond positively to warming WYTMIN, resulting from the largest increases in WYTMIN being in the coolest and wettest areas, and respond negatively to warming WYTMAX because the largest increases in WYTMAX are in the warmest and driest areas. The trade‐off of lowering temporal density against removing cloud‐contaminated years is justified as temporal density appears to have only a modest impact on trends and climate relationships until n ≤ 6, but multi‐year gaps are proportionally more influential. Gradual change analysis is likely to be less sensitive to n than abrupt change. These data can be used to answer critical questions regarding the influence of climate change and the suitability of management practices.