A new study highlights the significance of mixed forests in mitigating damage risks caused by climate change, emphasizing the role of diverse tree species in ensuring forest sustainability and economic stability.
Forests with a diverse range of tree species are significantly less prone to damage compared to monocultures, according to a new study conducted by researchers from Umeå University and the Swedish University of Agricultural Sciences in Uppsala. This finding is particularly crucial as climate change continues to present new challenges for forest ecosystems worldwide.
Fungi, insects, fires and large herbivores, such as moose, are natural contributors to tree damage in Swedish forests. The study reveals that as our climate warms, these types of damage are expected to become more prevalent and severe.
The researchers analyzed 15 years of data from across Sweden to determine which damages are most common and the primary factors influencing tree susceptibility.
“In a warmer climate with more extreme weather and new pest organisms, and with a more intense forestry, forest damages are expected to become more common and more severe. It is therefore important to understand causes of forest damages and whether it can be prevented,” lead author Micael Jonsson, an associate professor of environmental science in the Department of Ecology and Environmental Science at Umeå University, said in a news release.
The Swedish national forest inventory, which began collecting data on forest damages in 2003, provided the basis for this extensive research. The results indicate that wind and snow are the most frequent causes of tree damage, followed by forestry activities and fungal infections. Moose and other large cervids rank fifth among the causes.
Alarmingly, 94% of all trees showed some kind of damage. Coniferous trees and younger stands were the most at risk, particularly in the warmer regions of Sweden. The study highlights that stands with a limited number of tree species are more vulnerable compared to their more biodiverse counterparts.
“Our results show that there is a potential to reduce the risk of forest damages via a changed forest management. Especially, a higher proportion of broadleaf trees in the otherwise so coniferous-dominated production forest would result in fewer damages. We can, for example, see that the lodgepole pine, introduced by the forestry industry, has the highest risk of damage. Its introduction therefore counteracts a profitable forestry,” Jonsson added.
The findings suggest that increasing the number of tree species in production forests could act as a buffer against extensive damage, providing a form of insurance for forest ecosystems in a warming climate.
“We must adapt Swedish forests and forest management methods to a future warmer climate. Including more tree species in production forests seems to be an adaptation that could work!” added co-author Jan Bengtsson from the Swedish University of Agricultural Sciences.
While the data analyzed offers valuable insights, the researchers acknowledge some limitations. The cause behind a substantial proportion of the damages could not be established definitively, indicating a need for improved data quality in future forest damage inventories.
“The national forest inventory collects important data for our understanding of the forest, but when it comes to the damage inventory, the data quality needs to improve to be fully usable in forestry practices,” co-author Jon Moen, a professor in the Department of Ecology and Environmental Science at Umeå University, said in the news release.
The study, published in the journal Ecosphere, underscores the necessity of adaptive forest management practices that prioritize biodiversity to safeguard against the escalating risks posed by climate change.