Post-fire Environment & Management
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This study’s objective was to determine whether remnant/unburned sagebrush patches contribute to sagebrush recovery in surrounding burned areas surrounding them.
Key Findings:
While conventional wisdom is that sagebrush seeds remain close to the mother plant, we found that a measurable percentage of seeds travel up to tens of meters. Remnant patches of sagebrush after fire could contribute to natural regeneration in surrounding landscapes. However, seed arrival was highly variable between sites and work remains to be done to predict where natural regeneration will be sufficient to rehabilitate sagebrush steppe after wildfire.
Description: Landscapes of the Inland West are deeply affected by 100+ years of fire exclusion, the loss of indigenous burning, and expansion and densification of many forests. Today, anthropogenic climate change and wildfires are modifying the structure and composition of forests across the West at rates that far exceed adaptation and restorative treatments. Fires that occur during the forest planning process can delay project implementation for years, further hindering the pace of restoration activities. Landscape evaluations and prescriptions are needed so that managers can assess the work of wildfires on affected landscapes; the topic of this webinar.
Presenters and research team: Andrew Larson, C. Alina Cansler, Derek Churchill, Paul Hessburg Sr., Sean Jeronimo, Van Kane, Jim Lutz, and Nicholas Povak.
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Shifts from longer seasonal snowpacks to shorter, ephemeral snowpacks (snowpacks that persist for <60 days) due to climate change will alter the timing and rates of water availability. Ephemeral snowmelt has less predictable timing and lowers soil water availability during the growing season. The Great Basin, United States is an ideal system to study snow ephemerality across a broad climate gradient. To identify the climatic controls on snow ephemerality, we analysed moderate resolution imaging spectroradiometer (MODIS) snow‐covered products from water years 2001–2015 using an object‐based mapping approach and a random forest model. Winter temperature and precipitation were the most influential variables on the maximum snow duration. We predict that warming the average winter air temperature by 2 and 4°C would reduce the areal extent of seasonal snow by 14.7 and 47.8%, respectively (8.8% of the Great Basin’s areal extent is seasonal in the historical record), with shifts to ephemeral snowpack concentrated in lower elevations and warmer regions. The combination of warming and interannual precipitation variability (i.e., reductions of 25%) had different effects on vegetation types. Vegetation types that have had consistent seasonal snow cover in their historical record are likely to have lower resilience to a new hydrologic regime, with earlier and more intermittent snowmelt causing a longer but drier growing season. Implications of increased snow ephemerality on vegetation productivity and susceptibility to disturbance will depend on local topography, subsurface water storage, and physiological adaptations. Nevertheless, patterns found in this study can help target management intervention to species that are most at risk.
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In coniferous western forests, recent widespread tree mortality provided opportunities to test the long-held theory that forest cover loss increases water yield. We reviewed 78 studies of hydrologic response to standing-replacing (severe wildfire, harvest) or nonstand-replacing (drought, insects, low-severity wildfire) disturbances, and reassessed the question: Does water yield or snowpack increase after forest disturbance? Collective results indicate that postdisturbance streamflow and snowpack may increase, not change, or even decrease, and illuminate factors that may help improve predictability of hydrologic response to disturbance. Contrary to the expectation that tree mortality reduces evapotranspiration, making more water available as runoff, postdisturbance evapotranspiration sometimes increased—particularly following nonstand-replacing disturbance—
because of (a) increased evaporation resulting from higher subcanopy radiation, and (b) increased transpiration resulting from rapid postdisturbance growth. Postdisturbance hydrologic response depends on vegetation structure, climate, and topography, and new hypotheses continue to be formulated and tested in this rapidly evolving discipline.
Webinar recording.
Description: Among the values at risk from wildfire are community drinking water supplies, as forested watersheds on public land are often a primary or significant source of drinking water. In some places across the West, watershed protection partnerships have formed to address this threat by bringing together the stakeholders of these watersheds for collaborative planning and investment in source water protection. This webinar will explore the concept of watershed protection partnerships and how they span organizational boundaries for collective action to address wildfire and other risks. We will offer lessons learned from how these partnerships have been implemented in Colorado and New Mexico, and direct implications and applications for communities in Oregon.
Presenters: Heidi Huber-Stearns, University of Oregon; Emily Jane Davis, Oregon State University
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Our findings are consistent with other studies in showing that visitation losses do happen after wildfire but are short-lived and may differ between day and overnight users.· Although visitors were often saddened to see the burned landscape, their recreation experiences and satisfaction appeared largely unchanged.· Distributing up-to-date information about conditions at recreation destinations may be useful for potential visitors concerned about smoke and wildfire.· Recreationists substitute between recreation destinations or seasons to avid wildfire or smoke. Managers may do well to prepare for receiving visitors displaced by wildfire or smoke and having more visitors outside primary recreation seasons.
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Managers can use the First Order Fire Effects Model (FOFEM) when planning prescribed burns to achieve mortality-related objectives and for creating post-fire salvage guidelines to predict which trees will die soon after fire. Of the preceding observations, 13,460 involved trees that burned twice. Researchers evaluated the post-fire tree mortality models in FOFEM for 45 species. Approximately 75% of models tested in the FOFEM had either excellent or good predictive ability. Models performed best for thick-barked conifer species. Models tend to overpredict mortality for conifers with moderate bark thickness and underpredict mortality in primarily angiosperms or thin-barked conifers. Managers who rely on these models can use the results to (1) be aware of the uncertainty and biases in model predictions and (2) choose a threshold for assigning dead and live trees that optimizes certainty in either identifying or predicting live or dead individuals.
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Study objectives were (1) to quantify the magnitude and direction of change in the cover of native and exotic plant functional groups in relation to their exposure to fire; (2) to relate plant community changes to their historical composition, exposure to fire, and environmental conditions; and (3) to test for consistency of trends revealed by vegetation cover data derived from field plots and Landsat images. Results suggest that burned areas historically occupied by sagebrush‐dominated plant communities may have been invaded by exotic annuals prior to burning, possibly because of prior land uses, and after burning, have now transitioned to a persistent herbaceous‐dominated state. This type of state transition has important consequences for forage quality, wildlife habitat, soil nutrients, and future disturbances, such as drought and wildfire.
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Erosion of soil carbon (C) and nitrogen (N) following severe wildfire may have deleterious effects on downstream resources and ecosystem recovery. Although C and N losses in combustion and runoff have been studied extensively, soil C and N transported by post-fire erosion has rarely been quantified in burned landscapes. To better understand the magnitude and temporal pattern of these losses, we analysed the C and N content of sediment collected in severely burned hillslopes and catchments across the western USA over the first 4 post-fire years.
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Wildland fires in the contiguous United States (CONUS) have increased in size and severity, but much remains unclear about the impact of fire size and burn severity on water supplies used for drinking, irrigation, industry, and hydropower. While some have investigated large-scale fire patterns, long-term effects on runoff, and the simultaneous effect of fire and climate trends on surface water yield, no studies account for all these factors and their interactions at the same time. In this report, we present critical new information for the National Cohesive Wildland Fire Management Strategy—a first-time CONUS-wide assessment of observed and potential wildland fire impacts on surface water yield. First, we analyzed data from 168 fire-affected locations, collected between 1984 and 2013, with machine learning and used climate elasticity models to correct for the local climate baseline impact.