Post-Wildfire Restoration of Structure, Composition, and Function in Southwestern Ponderosa Pine and Warm/Dry Mixed-Conifer Forests
During the last several decades, uncharacteristically large wildfires have occurred at an increasing rate in the frequent-fire forests of the western United States (Westerling et al. 2006). These extensive and severely burned forests represent a serious conservation concern and restoration need. Indeed, Fulé et al. (2013, p.4) remarked that “large uncharacteristic wildfires pose one of the greatest risks to ecosystem integrity in the 21st century.” Such fires may be pushing forests in the western United States toward a “tipping point” that may lead to permanent changes in structure and composition, loss of carbon into the atmosphere and loss of carbon stocks (Hurteau and North 2009, North and Hurteau 2011, Hurteau et al. 2011), and changes in hydrological function (Dore et al. 2012, Adams 2013). Forests degraded by extensive high-severity fire often also exhibit accelerated soil erosion and subsequent loss of soil productivity, expansions or invasions of non-native plant populations, loss of wildlife habitat; damaged watersheds and degraded water quality to connected streams, and/or vegetation type conversions.
Federal land management agencies have formally separated post-fire rehabilitation into short-term stabilization and long-term restoration measures. The U.S. Forest Service Burned Area Emergency Response (BAER) program includes well-researched emergency treatments “to stabilize the burned area, protect public health and safety, and reduce the risk of additional damage to valued resources, such as water supply systems, aquatic habitat and roads” (Robichaud 2009). An immediate goal of BAER is to have protection in place prior to the first damage-producing rain event following the fire. Rehabilitation activities are implemented and can be monitored for up to three years after wildfire, and include the repair of facilities and mitigation of land and resources that are unlikely to recover on their own (Robichaud 2009). Longer-term post- fire restoration efforts have generally received much less attention, although the increasing occurrence of very large wildfires has prompted more attempts to articulate and evaluate long-term strategies (Long et al. in press).
As opposed to emergency rehabilitation, ecological restoration focuses on assisting the recovery of characteristic ecological structure, process, and function. This requires an understanding of natural ranges of variability for these key attributes as well as development of reference conditions to guide management activities (Egan and Howell 2001, Margolis et al. 2013). In addition, restoration activities demand long-term commitment and evaluation. However, given the altered conditions that sometimes follow high-severity fires in previously degraded forests, successful restoration to a desired state may be difficult and costly (Scheffer et al. 2001).
This working paper describes the goals of post-wildfire forest restoration, identifies the unique challenges and opportunities for management of severely burned large patches, and develops principles for restoring forests that have been burned by high-severity wildfires.
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