Fire Ecology & Effects

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The Joint Fire Science Program: 20 years of innovation and contributions

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In 1998, the Joint Fire Science Program (JFSP) was statutorily authorized as a joint partnership between the U.S. Department of the Interior and the U.S. Department of Agriculture Forest
Service. The program provides leadership to the wildland fire science community by identifying high-priority fire science research needs that will enhance the decisionmaking ability of
managers to meet their objectives. This publication celebrates and describes the JFSP’s contributions to and impact on the wildland fire community over the past 20 years.

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Online Fire and Natural Resources Courses from the University of Idaho

Please visit the UI website for details about dates and timing.

The University of Idaho (UI) offers a variety of online fire and natural resources courses with Great Basin content.  These courses and degree programs can help you develop as a professional and succeed in fire and natural resources management. View the list of online courses or certificate and degree programs. Consider taking one or more online courses, a certificate or enroll in a degree program. This is a great option as many professionals are place-bound, face limits on travel budgets, and are challenged to effectively accomplish science-based management on the ground to address pressing needs for management and conservation in Great Basin ecosystems and beyond.

The Fire Ecology, Management and Technology Certificate and the Master of Natural Resources (MNR) degree can be completed entirely online — without ever coming to campus, and at in-state tuition rates for all.

As many professionals are place-bound and face limits on travel, these online training options can help practitioners accomplish science-based management on the ground to address land management challenges in the Great Basin and beyond.

Questions? Contact cnr-grad-studies@uidaho.edu

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Burn severity effects on plant diversity and composition in mixed conifer

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This study found that the understory plant community was not fundamentally altered by these fires and fire contributed to increased species diversity both locally and regionally, suggesting that low to moderate burn severity fire is a treatment that contributes to long-term maintenance of a diverse and productive understory. Individual species traits were significant drivers of understory species assemblages and, as future change in climate and fire regimes leads to shifts in species composition, anticipation of consequences will be important. Although invasive species occurred at low cover levels, noxious weeds and invasive annual grasses will continue to be management challenges, particularly in dry regions of mixed conifer forests.

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Repeated fires reduce plant diversity in low-elevation Wyoming big sagebrush (1984–2014)

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This study found that one fire fundamentally changed community composition and reduced species richness, and each subsequent fire reduced richness further. Alpha diversity decreased after one fire. Beta diversity declined after the third fire. Cover of exotics was 10% higher in all burned plots, and native cover was 20% lower than in unburned plots, regardless of frequency. Fire frequency and antecedent precipitation were the strongest predictors of beta diversity, while time since fire and vapor pressure deficit for the year of the fire were the strongest predictors of community composition. Given that a single fire has such a marked effect on species composition, and repeated fires reduce richness and beta diversity, we suggest that in lower elevation big sagebrush systems fire should be minimized as much as possible, perhaps even prescribed fire. Restoration efforts should be focused on timing with wet years on cooler, wetter sites.

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Impacts of multi-year drought on post-fire conifer regeneration

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The results of this study indicate that post-fire natural regeneration in the Blue Mountains over the last 20 years has generally been sufficient to maintain forest resilience. Recruitment differs dramatically, however, across sites. In burned areas with abundant surviving adult trees 100 m away or less and on north-facing slopes, hundreds or thousands of seedlings per hectare may establish within the first 10 to 15 years post-fire. In contrast, conifer densities in large high-severity burn patches (i.e., larger than 100 to 200 m in radius) with high overstory mortality, especially those on warmer sites, may be insufficient to meet local silvicultural guidelines or maintain forest ecosystem function without supplementary replanting. Some of these marginal sites may be susceptible to ecosystem state transitions to shrub or grasslands. The results of this study also suggest that as climate change causes temperatures to warm and increases the probability of growing season moisture deficits, Douglas-fir recruitment may decline in drought-prone sites. Ponderosa pine seedlings may be more resilient to warming conditions, though as warming continues they also will become vulnerable to drought stress.

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Effects of season and interval of Rx burns on carbon in ponderosa pine in southern Blue Mtns

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We did not detect a difference in mean pyrogenic carbon (PyC) concentration of the mineral soil between the spring burns and the unburned controls; however, the spring burn plots did contain a number of isolated pockets with very high concentrations of PyC, suggesting a patchier burn pattern for these plots. In general, there was no detectable difference in any of the response variables when comparing the various prescribed burn treatments to one another. Reestablishing fire in these forests resulted in minor effects on the PyC concentration and pH, which may have beneficial impacts on soil carbon and available nutrients, while having few effects on other soil characteristics. This suggests that the application of low severity prescribed fires should result in little detrimental change to soils of ponderosa pine forests of the Southern Blue Mountains, while achieving management objectives such as reduction of surface fuels.

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Do trends in climate influence the increase in high-severity wildfire in the southwestern US from 1984 to 2015?

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Over the last 30 years, in woodland and forested ecosystems across the southwestern US, there has been an increasing trend in fire activity. Altered land use practices and more recent changes in precipitation patterns and warmer temperatures are widely thought to contribute to departures in fire regimes toward more frequent and larger fires with more extreme fire behavior that threatens the persistence of the various forested ecosystems. We examined climate-fire relationships in these vegetation types in Arizona and New Mexico using an expanded satellite-derived burn severity dataset that incorporates over one million additional burned hectares analyzed as extended assessments to the MTBS project’s data and five climate variables from PRISM. Climate-fire relationships were identified by comparing annual total area burned, area burned at high/low severity, and percent high severity regionally with fire season (May-August) and water year (October-September) temperature, precipitation, and vapor pressure deficit (VPD) variables. The high severity indicators were also derived for each fire individually to see if climate-fire relationships persist at the scale of the individual fire. Increasing trends toward more arid conditions were observed in all but two of the climate variables. Furthermore, VPD-fire correlations were consistently as strong or more correlated compared to temperature or precipitation indicators alone, both regionally and at the scale of the individual fire. Thus, our results support the use of VPD as a more comprehensive climate metric than temperature or other water-balance measures to predict future fire activity. Managers will have to face the implications of increasing high severity fire as trends in climate toward warmer and drier conditions become an increasingly dominant factor in driving fire regimes towards longer and more intense fire seasons across the Southwest.

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Severe fire weather and intensive forest management increase fire severity in a multi‐ownership landscape

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Many studies have examined how fuels, topography, climate, and fire weather influence fire severity. Less is known about how different forest management practices influence fire severity in multi‐owner landscapes, despite costly and controversial suppression of wildfires that do not acknowledge ownership boundaries. In 2013, the Douglas Complex burned over 19,000 ha of Oregon & California Railroad (O&C) lands in Southwestern Oregon, USA. O&C lands are composed of a checkerboard of private industrial and federal forestland (Bureau of Land Management, BLM) with contrasting management objectives, providing a unique experimental landscape to understand how different management practices influence wildfire severity. Leveraging Landsat based estimates of fire severity (Relative differenced Normalized Burn Ratio, RdNBR) and geospatial data on fire progression, weather, topography, pre‐fire forest conditions, and land ownership, we asked (1) what is the relative importance of different variables driving fire severity, and (2) is intensive plantation forestry associated with higher fire severity?

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Effects of season and interval of prescribed burns on pyrogenic carbon in ponderosa pine stands in the southern Blue Mountains, Oregon

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In ponderosa pine (Pinus ponderosa) forests of the western United States, prescribed burns are used to reduce fuel loads and restore historical fire regimes. The season of and interval between burns can have complex consequences for the ecosystem, including the production of pyrogenic carbon (PyC). PyC plays a crucial role in soil carbon cycling, displaying turnover times that are orders of magnitude longer than unburned organic matter. This work investigated how the season of and interval between prescribed burns affects soil organic matter, including the formation and retention of PyC, in a ponderosa pine forest of eastern Oregon.

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Effects of wildfires and fuel treatments on watershed water quantity across the US

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Scientists at the Southern Research Stations of the US Forest Service combined the hydrometeorological and fire data for 168 fire-affected areas in the contiguous United States collected between 1984 and 2013. This enabled them to determine when wildland fires can affect the annual amount of flow in rivers, and to create a suite of climate and wildland fire impact models adapted to local conditions.

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