Managing forest resources for resilience is a top priority for the USDA Forest Service. While fuels reduction and restoration can create more resilient forests and reduce fire risk, these activities also might alter the habitat of sensitive old-forest species, such as the spotted owl, and worsen their ongoing declines. Such concerns have slowed the implementation of management activities that might curb stand-replacing fires, including tree thinning and prescribed fire.
Solving this conundrum involves understanding whether or how the potential negative short-term impacts of restoration on spotted owls can be outweighed by reducing habitat loss to future severe wildfires. To address this question, we developed a novel bioregional-scale severe fire model linked to climate and vegetation (e.g., fuels) conditions that could be used to predict future severe fire activity at fine scales (30-m resolution). We also developed a spotted owl occupancy model linked to forest conditions and severe fire exposure. Both the fire model and the occupancy model were constructed using decades of empirical data.
The fire model produced annual realizations of severe fire occurrence across the Sierra Nevada through mid-century that fed into the occupancy model. The behavior of both models was linked to a factorial design that varied the extent and location of simulated restoration activities. Specifically, treatments either were restricted from spotted owl territories, or were allowed to occur within territories; and under both of these scenarios, treatments were simulated across 20-60 percent of the Sierra Nevada.
This effort sought to answer two central questions about forest restoration. First, can restoration effectively reduce future severe fire activity in a changing climate? Second, can restoration provide co-benefits to spotted owls?
Jones, Gavin M., et al. 2022. Forest restoration limits megafires and supports species conservation under climate change. Frontiers in Ecology and the Environment.