Wildfires prompt stray tree species to move faster, study finds
Plants and trees choose where to take root based on the environment around them, and as the global climate changes, trees and other plants move: movements that are accelerated by the spread of wildfires, according to a new study.
Tree and animal species are expected to move to cooler and wetter places as the world warms, in order to find more suitable habitats for growth and reproduction.
For plants crawling regularly to higher altitudes, this migration is not really slow, with an average rate of about 1.5 meters (or about 5 feet) per year.
If forest fires help some species take precedence over others, it is an important consideration for the management and preservation of forests, especially since the factors causing this wandering of trees are not. not fully understood by scientists yet.
“Complex and interdependent forces are shaping the future of our forests”, says plant biologist Avery Hill from Stanford University in California.
“We have tapped into an immense amount of ecological data in hopes of contributing to a growing body of work aimed at managing these ecosystem transitions.”
Researchers analyzed a total of 74,069 forest patches in nine states in the western United States, examining distances between mature trees and new seedlings to estimate the speed at which tree species migrated from one place to place.
Of eight species that seemed to move, two – Douglas fir (Pseudotsuga menziesii) and the live oak canyon (Quercus chrysolepis) – showed signs of larger changes in areas affected by forest fires compared to areas that had not been burned in recent years.
While this particular study does not examine the reasons for this in detail, the researchers suggest that the ability of species such as the canyon living oak to germinate quickly after a fire gives it an advantage. Coupled with canopy destruction, a forest fire could benefit some migratory plant species over others.
That’s probably not the whole story here, however.
“Forest fires, because they reduce vegetation cover and thus certain aspects of plant-plant competition, provide an entry point to explore the hypothesis that eliminating competitors can accelerate the expansion of the forest. ‘climate-related range,’ write the researchers in their paper.
“Of course, the effects of fire on community assembly certainly go beyond reducing plant-to-plant competition, and other aspects of fire ecology could influence range changes. climate related. “
There is evidence that some trees are unable to keep pace with climate change – potentially leaving some species stranded in unsuitable habitats for them, as they are unable to move quickly enough to new areas.
This is where measures such as controlled burning could come into play. Small-scale, low-intensity fires can be created artificially to limit forest fires and manage forests, and they may also have a role to play. in the response to climate change.
As the researchers say, however, the evidence is currently incomplete. Different tree species will respond in different ways, and the impacts of forest fires extend far beyond tree migration – so further studies will be needed.
“This study highlights a natural mechanism that can help forests stay healthy, even in the face of small amounts of climate change,” says biologist Chris Field from Stanford University.
“It also illustrates how ecosystem processes often have multiple levels of control, a feature that emphasizes the value of detailed understanding for effective management.”
The research was published in Nature Communication.