Wildfires are making trees 'move' across the US as climate conditions change – with species shifting towards cooler and wetter sites.
Researchers have shown that wildfire is accelerating the process, probably by reducing competition from established species.
"Complex, interdependent forces are shaping the future of our forests," said study lead author Avery Hill, a graduate student in biology at Stanford's School of Humanities & Sciences.
"We leveraged an immense amount of ecological data in the hopes of contributing to a growing body of work aimed at managing these ecosystem transitions."
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As the climate changes, animal and plant species are shifting their ranges toward conditions suitable for their growth and reproduction.
Previous research has shown that plant ranges are shifting to higher, cooler elevations at an average rate of almost five feet per year.
Sometimes these range shifts lag behind the rate of climate change, suggesting that some species may become stranded in unsuitable habitats.
The researchers used US Forest Service data collected from more than 74,000 plots across nine western states.
They compared the rate of range shifts between places that were burned by wildfire and places that were not.
Two – Douglas fir and canyon live oak – had larger range shifts in areas that burned than in areas that did not.
The researchers suggested that burned areas with their open canopies and scorched understory presented less competition from other plant species.
The findings demonstrate not only that fire can accelerate tree migration, but that some species may be slowing the range shifts of others through competition.
"This study highlights a natural mechanism that can help forests remain healthy, even in the face of small amounts of climate change," said study co-author Chris Field, the Perry L McCarty director of the Stanford Woods Institute for the Environment.
"It also illustrates the way that ecosystem processes often have several layers of controls, a feature that emphasises the value of detailed understanding for effective management."
Earlier this year, a US study showed that wildfires are causing extra deaths from COVID-19.
Wildfires release fine particles that can affect people’s airways, and make more people catch coronavirus and die from it.
The study showed that thousands of extra COVID cases and deaths in California, Oregon and Washington between March and December 2020 may have been caused by fine particulate air pollution released in wildfire smoke.
Areas with high levels of the pollution saw an increase of up to 65.9% in COVID deaths due to the fine particles that can affect airways.
The pollution (technically known as PM2.5 pollution) was linked to premature death, asthma, chronic obstructive pulmonary diseases (COPD), and other respiratory illnesses.
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