Synergistic effects on fire hazard from combined linear fuel breaks and mosaic fuel treatments

Abstract Background Designing large-scale fuel reduction programs has increasingly become a complex planning process owing to multifaceted fire management objectives that vary in space and time. In many fire-prone systems, fuel management strategies rely on fuel break networks (FBN) and fuel treatment mosaics (FTM) to mitigate wildfire impacts. While both archetypes are being widely implemented as part of newer fire management initiative, managers must decide how to allocate investments to best achieve desired long-term outcomes. This problem creates a new spatial prioritization paradigm that has long-term implications on fire management but has yet to be explored in sufficient detail to make management recommendations. In this study, we simulated treatment scenarios in four diverse regions in Portugal where the two archetypes were simultaneously implemented under different spatial arrangements to understand how they can be combined to reduce fire hazard. Results The results indicated that co-implementation of FTM in the vicinity of FBN significantly improved multiple wildfire management metrics including containment probability, reduction in burned area and high-intensity fire occurrence. This synergistic effect was observed across the spectrum of land use types ranging from forest to agro-pastoral regions and associated fire regimes. The overall contribution of the FBN to reducing burned area was higher in forest-dominated areas whereas FTM had a consistent impact in terms of reducing high-intensity burned area. Conclusions The results suggest that optimizing the co-implementation archetypes needs to consider local land use patterns and associated fire regimes to optimize investments in the alternative fuel management archetypes.