Reburns test the resilience of subalpine forests and reveal opportunities for adaptation

In subalpine forests of the Northern Rockies, short-interval high-severity wildland fires are symptomatic of emerging changes in fire regimes. Evidence of forest conversion to non-forest and prolonged establishment windows is accumulating. However, fire-prone forests are diverse in species’ traits and climatic setting, enabling varied responses to changing drivers. Recent studies of tree regeneration after reburns show how they undermine fire-adaptive traits and alter the microclimate that controls seedling establishment. Untangling these mechanisms can help us anticipate the outcomes of natural and managed regeneration and point toward promising interventions.
As indications of fire-regime change emerge, forecasts of future fire activity and the vulnerability of forests to fire-driven transformation are needed. Making such forecasts is complicated by inextricable links among climate, vegetation, and fire, leading to divergent expectations depending on how these relationships are represented. Area burned will likely continue to increase in response to climate and a management-driven fire deficit. However, vegetation feedbacks to burn severity, where persistent fire-driven changes in ecosystem structure and composition alter subsequent fire behavior and ecosystem dynamics, are still poorly constrained.
I will present a novel method of forecasting exposure to climate and fire-regime change that honors the multivariate nature of fire. We mapped pyroclimate exposure and changes in burn severity at the fireshed level under 2° C of warming and identified where species’ traits will be aligned with future conditions. This knowledge can support stewardship to adapt ecosystems to likely future conditions, rather than restoring them to historical baselines that may not be supported by future climates.


Tyler Hoecker