Research and Publications
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Past and current forest management affects wildland fire smoke impacts on downwind human populations. However, mismatches between the scale of benefits and risks make it difficult to proactively manage wildland fires to promote both ecological and public health. Building on recent literature and advances in modeling smoke and health effects, we outline a framework to more directly quantify and compare smoke impacts based on emissions, dispersion, and the size and vulnerability of downwind populations across time and space. We apply the framework in a case study to demonstrate how different kinds of fires in California’s Central Sierra Nevada have resulted in very different smoke impacts.
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In this study cut bolts of Great Basin bristlecone pine and two susceptible host tree species, limber (P. flexilis) and lodgepole (P. contorta) pines were infested with adult mountain pine beetles and compared offspring performance. To investigate the potential for variation in offspring performance among mountain pine beetles from different areas, we tested beetles from geographically-separated populations within and outside the current range of Great Basin bristlecone pine. Although mountain pine beetles constructed galleries and laid viable eggs in all three tree species, extremely few offspring emerged from Great Basin bristlecone pine, regardless of the beetle population. Our observed low offspring performance in Great Basin bristlecone pine corresponds with previously documented low mountain pine beetle attack preference. A low preference-low performance relationship suggests that Great Basin bristlecone pine resistance to mountain pine beetle is likely to be retained through climate-driven high-elevation mountain pine beetle outbreaks.
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Fuel, aridity, and ignition switches were all on in 2017, making it one of the largest and costliest wildfire years in the United States (U.S.) since national reporting began. Anthropogenic climate change helped flip on some of these switches rapidly in 2017, and kept them on for longer than usual. Anthropogenic changes to the fire environment will increase the likelihood of such record wildfire years in the coming decades. The 2017 wildfires in the U.S. constitute part of a shifting baseline in risks and costs; meanwhile, effective policies have lagged behind, leaving communities highly vulnerable. Policy efforts to build better and burn better, in the U.S. as well as in other nations with flammable ecosystems, will promote adaptation to increasing wildfire in a warming world.
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Decades of overgrazing and wildfire suppression have let juniper trees grow large and spread far across sagebrush country, reducing habitat for sage grouse and other wildlife, and creating conditions for catastrophic wildfires.
In areas where fire is no longer a safe treatment, many land managers are stepping up to fill the role once played by wildfire.
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This paper identifies actions needed in order to improve provenance decision-making. Priority actions include embedding provenance trials into restoration projects; developing dynamic, evidence-based provenance policies; and establishing stronger research-practitioner collaborations to promote provenance choice and implement research outcomes for future restoration projects. Understanding how a changing climate will impact future restoration projects is also an important consideration when making decisions around provenance.
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This study found that fire frequency and a coarse measure of grazing use were not highly predictive of seed bank dynamics, with the exception that sites that burned <10 years ago had greater above-vs. below-ground similarity. Shrub cover predicted multiple below-ground characteristics: Ericameria nauseosa was associated with increased density of introduced species, Chrysothamus viscidiflorus was associated with increased densities of native annual species, and Artemisia tridentata was associated with increased richness of rare native species. Shrub cover estimates were predictive of seed bank composition, and suggest that areas dominated by A. tridentata would have the greatest restoration potential within their seed banks.
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This Rangelands on the Edge (ROTE) project improves our understanding of the fate of rangelands from historical, present day, and future perspectives by describing human modification, fragmentation, and future residential growth projections for rangeland-dominated vegetation. Since pre-European settlement, some 340 million acres (over 34 percent) of rangelands, particularly in the Great Plains, have been converted to alternative land uses, especially intensive agriculture (croplands, pastureland). Approximately 11 percent of private rangelands are likely to experience significant increases in housing development over the next 15 years.
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Wildfires are far more likely to result in harmful air quality and public health impacts than prescribed fires because they are unplanned and typically are much larger. Wildfires also last longer, and burn and consume (on average) more vegetation per acre than prescribed fires.
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This study examines differences in temperature, vapour pressure deficit, fuel moisture and wind speed for large and small lightning- and human-caused wildfires during the initial days of fire activity at ecoregion scales across the US. Large fires of both human and lightning origin occurred coincident with above-normal temperature and vapour pressure deficit and below-normal 100-hour dead fuel moisture compared with small fires. Large human-caused wildfires occurred, on average, coincident with higher wind speeds than small human-caused wildfires and large lightning-caused wildfires. These results suggest the importance of winds in driving rapid fire growth that can allow fires to overcome many of the factors that typically inhibit large human-caused fires. Additionally, such findings highlight the interplay between human activity and meteorological conditions and the importance of incorporating winds in modelling large-fire risk in human-dominated landscapes.
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This report presents a new fuel sampling method, called the photoload sampling technique, to quickly and accurately estimate loadings for six common surface fuel components (1 hr, 10 hr, 100 hr, and 1000 hr downed dead woody, shrub, and herbaceous fuels). This technique involves visually comparing fuel conditions in the field with photoload sequences to estimate fuel loadings. Photoload sequences are a series of downward-looking and close-up oblique photographs depicting a sequence of graduated fuel loadings of synthetic fuelbeds for each of the six fuel components.