In Alaska, wildfires help prevent future burns. Researchers question if that feedback loop will hold
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…
In Alaska's boreal forests, a negative feedback loop exists between wildfires and vegetation, influencing fire size and likelihood. This relationship helps balance fire activity, but scientists are uncertain how it will change with climate warming. Researchers analyzed data from 1984 to 2020 on Alaskan wildfires, finding that recent burns had a strong negative influence on fire activity, with young vegetation reducing reburning rates by 1-3 orders of magnitude compared to older forests.
A model estimates that without this feedback loop, Alaska would have experienced five times more wildfires over the past 40 years. However, extreme fire weather weakened this relationship, especially in younger forests, suggesting that climate change could weaken the protective role of younger vegetation. Despite this, past fires still limit new fire activity in Alaska more strongly than in the contiguous Western United States, where deciduous trees grow back more quickly and fuel replacement takes longer.
These findings could help fire managers assess the likelihood of a burned area suppressing future fires based on its age and current fire weather.
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