This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: In Alaska's boreal forests, a negative feedback loop between wildfires and vegetation plays an important role in governing the size and likelihood of fires. Wildfires clear out mature forests, allowing them to be replaced by less flammable young forests that temporarily suppress fires.
This relationship helps balance fire activity, but to what extent is unclear. Scientists are also uncertain how it will change as the climate warms. Gaglioti and his team use remotely sensed data on Alaskan wildfires between 1984 and 2020 to examine fires that encounter previously burned areas.
They use a logistic regression model to assess how strongly young vegetation resists wildfire and whether warmer, drier conditions can affect that resistance. The research is published in the Journal of Geophysical Research: Biogeosciences. The authors found that younger vegetation in recently burned areas has historically exerted a strong negative influence on fire activity.
Reburning rates in younger forests were 1–3 orders of magnitude lower than rates in older forests, with the burned-area perimeter often acting as a barrier to later encroaching fires. A simple model of landscape burning estimates that without this negative feedback loop, Alaska would have seen five times more wildfires during the past 40 years, the authors say. Extreme fire weather significantly weakened this relationship, especially in younger forests, the authors found.
This is in line with previous research and suggests that a changing climate could weaken the suppressive role of younger vegetation. Nevertheless, future climate change, which the researchers modeled by treating historically extreme fire years as normal, does not completely negate the suppressive effect of past burning. Comparing their results with similar studies in the contiguous Western United States, the authors found that past fires limited new fire activity twice as strongly in Alaska, where less flammable deciduous trees grow back more quickly and the replacement of ladder fuel (fuel that carries fire from the forest floor to tree crowns) takes longer.
Their results could be useful to fire managers, who often use previously burned areas as natural firebreaks. Using the model, managers could assess how likely a given burned area is to suppress new fire activity based on its age and current fire weather. Gaglioti et al, The Strength of Fuel Self‐Regulation in Alaska's Wildfire Regimes, Journal of Geophysical Research: Biogeosciences (2026).
Extract — continue reading at the source.
