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1. Baptism of Fire: Modeling the Effects of Prescribed Fire on Lyme Disease

   https://doi.org/10.1155/2022/5300887  

   Guo, Emily ; Agusto, Folashade B. ( May 2022 , Canadian Journal of Infectious Diseases and Medical Microbiology)

   Di Luca, Marco (Ed.)

   Recently, tick-borne illnesses have been trending upward and are an increasing source of risk to people’s health in the United States. This is due to range expansion in tick habitats as a result of climate change. Thus, it is imperative to find a practical and cost-efficient way of managing tick populations. Prescribed burns are a common form of land management that can be cost-efficient if properly managed and can be applied across large amounts of land. In this study, we present a compartmental model for ticks carrying Lyme disease and uniquely incorporate the effects of prescribed fire using an impulsive system to investigate the effects of prescribed fire intensity (high and low) and the duration between burns. Our study found that fire intensity has a larger impact in reducing tick population than the frequency between burns. Furthermore, burning at high intensity is preferable to burning at low intensity whenever possible, although high-intensity burns may be unrealistic due to environmental factors. Annual burns resulted in the most significant reduction in infectious nymphs, which are the primary carriers of Lyme disease. 

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2. Effects of Fire Intensity and Abiotic Factors on Persistence of an Encroaching Woody Species

   Starns, H. D. ; Wonkka, C. L. ; Lodge, A. G. ; Twidwell, D. ; Treadwell, M. L. ; Kavanagh, K. L. ; Dickinson, M. B. ; Tolleson, D. R. ; Rogers, W. E. ( May 2019 , Proceedings of the Albuquerque Fire Behavior and Fuels Conference)

   Over the past century, rangelands worldwide have experienced changes in vegetation cover and structure, many transitioning from grass-dominated to shrub-dominated systems (Archer et al. 2017; Fuhlendorf et al. 2017). In North America, such transitions are primarily a consequence of livestock management and fire exclusion practices of Euro-American settlers (Bray 1904; Archer 1989; Fuhlendorf and Smeins 1997). These shrub-dominated systems are often less productive for wildlife and livestock and may have crossed a threshold which cannot be reversed via common restoration practices such as prescribed fire (Ansley and Castellano 2006; Ratajczak et al. 2016). Oftentimes, the inability of prescribed fire to succeed at crossing this threshold is the result of insufficient fuel loading or inadequate fire intensity due to prescription parameters (Havstad and James 2010; Twidwell et al. 2016). However, recent work has demonstrated that burning under more extreme conditions (e.g. higher temperatures, lower fine fuel moisture) can slow or change the course of encroachment (Twidwell et al. 2013; Twidwell et al. 2016). Many encroaching shrub species are capable of persisting after fire via resprouting from protected buds (Bond and Midgley 2001). Such mechanisms pose challenges for land managers, particularly because resprouting often results in a higher number of stems per individual plant. Mesquite (Prosopis spp.) shrubs are well-known for their ability to persist to varying degrees following disturbance due to fire, chemical, and mechanical treatments. Due to historical livestock management and fire suppression practices, honey mesquite (Prosopis glandulosa) has increased in dominance and abundance in the southern Great Plains since the beginning of Euro-American settlement (Bray 1904; Archer 1989). Although prescribed fire has increased in acceptance as a method to reduce encroachment of mesquite, low-intensity fires performed during the dormant season rarely cause mortality (Wright and Bailey 1980; Ansley et al. 1998), especially when they are performed as a single treatment rather than as part of a comprehensive management plan. However, recent studies have demonstrated that more intense fires conducted outside the dormant season are capable of reducing resprouters (including mesquite), particularly during periods of drought (Twidwell et al. 2016). We evaluated impacts of fire intensity and abiotic factors on persistence of honey mesquite, a species of concern for managers in the southern Great Plains. 

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3. Adapting western North American forests to climate change and wildfires: ten common questions

   https://doi.org/10.1002/eap.2433  

   Prichard, Susan J. ; Hessburg, Paul F. ; Hagmann, R. Keala ; Povak, Nicholas A. ; Dobrowski, Solomon Z. ; Hurteau, Matthew D. ; Kane, Van R. ; Keane, Robert E. ; Kobziar, Leda N. ; Kolden, Crystal A. ; et al ( August 2021 , Ecological Applications)

   null (Ed.)

   We review science-based adaptation strategies for western North American (wNA) forests that include restoring active fire regimes and fostering resilient structure and composition of forested landscapes. As part of the review, we address common questions associated with climate adaptation and realignment treatments that run counter to a broad consensus in the literature. These include: (1) Are the effects of fire exclusion overstated? If so, are treatments unwarranted and even counterproductive? (2) Is forest thinning alone sufficient to mitigate wildfire hazard? (3) Can forest thinning and prescribed burning solve the problem? (4) Should active forest management, including forest thinning, be concentrated in the wildland urban interface (WUI)? (5) Can wildfires on their own do the work of fuel treatments? (6) Is the primary objective of fuel reduction treatments to assist in future firefighting response and containment? (7) Do fuel treatments work under extreme fire weather? (8) Is the scale of the problem too great – can we ever catch up? (9) Will planting more trees mitigate climate change in wNA forests? and (10) Is post-fire management needed or even ecologically justified? Based on our review of the scientific evidence, a range of proactive management actions are justified and necessary to keep pace with changing climatic and wildfire regimes and declining forest successional heterogeneity after severe wildfires. Science-based adaptation options include the use of managed wildfire, prescribed burning, and coupled mechanical thinning and prescribed burning as is consistent with land management allocations and forest conditions. Although some current models of fire management in wNA are averse to short-term risks and uncertainties, the long-term environmental, social, and cultural consequences of wildfire management primarily grounded in fire suppression are well documented, highlighting an urgency to invest in intentional forest management and restoration of active fire regimes. 

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4. Decision Support for Landscapes with High Fire Hazard and Competing Values at Risk: The Upper Wenatchee Pilot Project

   https://doi.org/10.3390/fire7030077  

   Skinner, Haley K ; Prichard, Susan J ; Cullen, Alison C ( March 2024 , Fire)

   Background: Climate change is a strong contributing factor in the lengthening and intensification of wildfire seasons, with warmer and often drier conditions associated with increasingly severe impacts. Land managers are faced with challenging decisions about how to manage forests, minimize risk of extreme wildfire, and balance competing values at risk, including communities, habitat, air quality, surface drinking water, recreation, and infrastructure. Aims: We propose that land managers use decision analytic frameworks to complement existing decision support systems such as the Interagency Fuel Treatment Decision Support System. Methods: We apply this approach to a fire-prone landscape in eastern Washington State under two proposed landscape treatment alternatives. Through stakeholder engagement, a quantitative wildfire risk assessment, and translating results into probabilistic descriptions of wildfire occurrence (burn probability) and intensity (conditional flame length), we construct a decision tree to explicitly evaluate tradeoffs of treatment alternative outcomes. Key Results: We find that while there are slightly more effective localized benefits for treatments involving thinning and prescribed burning, neither of the UWPP’s proposed alternatives are more likely to meaningfully minimize the risk of wildfire impacts at the landscape level. Conclusions: This case study demonstrates that a quantitatively informed decision analytic framework can improve land managers’ ability to effectively and explicitly evaluate tradeoffs between treatment alternatives.

    

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5. Human influence on late Holocene fire history in a mixed-conifer forest, Sierra National Forest, California

   https://doi.org/10.1186/s42408-023-00245-9  

   Klimaszewski-Patterson, Anna ; Dingemans, Theodore ; Morgan, Christopher T. ; Mensing, Scott A. ( January 2024 , Fire Ecology)

   Understanding pre-1850s fire history and its effect on forest structure can provide insights useful for fire managers in developing plans to moderate fire hazards in the face of forecasted climate change. While climate clearly plays a substantial role in California wildfires, traditional use of fire by Indigenous people also affected fire history and forest structure in the Sierra Nevada. Disentangling the effects of human versus climatically-induced fire on Sierran forests from paleoecological records has historically proved challenging, but here we use pollen-based forest structure reconstructions and comparative paleoclimatic-vegetation response modeling to identify periods of human impact over the last 1300 years at Markwood Meadow, Sierra National Forest.

   We find strong evidence for anthropogenic fires at Markwood Meadow ca. 1550 – 1750 C.E., contemporaneous with archaeological evidence for fundamental shifts in Indigenous lifeways. When we compare our findings to five other paleoecological sites in the central and southern Sierra Nevada, we find evidence for contemporaneous anthropogenic effects on forest structure across a broad swath of cismontane central California. This is significant because it implies that late 19th and early twentieth century forest structure – the structure that land managers most often seek to emulate – was in part the result anthropogenic fire and precolonial resource management.

   We consequently suggest that modern management strategies consider (1) further incorporating traditional ecological knowledge fire practices in consultation with local tribal groups, and (2) using pollen-based reconstructions to track how forest composition compares to pre-1850 C.E. conditions rather than the novel forest states encountered in the late 20th and early twenty-first centuries. These strategies could help mitigate the effects of forecast climate change and associated megafires on forests and on socio-ecological systems in a more comprehensive manner.

    

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