By exposing seedlings to drought and heat in climate chambers, researcher Leonie Schönbeck aims to determine how trees will cope in the future. “The need to better understand drought and heat tolerance in trees is significant, as it helps us predict their vulnerability to climate change,” says Schönbeck.
As climate change progresses, the growing season is expected to become warmer and drier in nordic countries. While this could lead to improved tree growth in northern Sweden, it may also stress trees, resulting in increased forest damage and reduced timber production.
To tackle these challenges, researchers are striving to understand how different tree species can adapt to rising temperatures and drought conditions.
Schönbeck has dedicated her career to this research. Last autumn, she secured funding from Formas for four-years of fundamental research on how spruce, pine, birch, and oak respond to heat and drought. Her work extends beyond merely noting reduced growth; she seeks to understand why growth is affected.
“Different tree species have distinct strategies to endure drought and heat, which impacts their measured growth. For instance, some trees shed their leaves, while others expand their root systems,” Schönbeck explains.
The methods she employs are groundbreaking. At Alnarp, she places seedlings in climate chambers to simulate varying environmental conditions. She uses a portable device to measure photosynthesis in real time. Additionally, she will conduct traditional growth measurements on trees across different countries.
Today, various provenances of tree species are used in forest plantations, based on the idea that seedlings from different regions may grow better than local varieties. Schönbeck will compare seedlings from Switzerland, Germany, and both southern and northern Sweden to assess their resilience to a drier and warmer climate. The results could reveal differences in stress tolerance among provenances.
In the highly controlled climate chambers, she can stress-test the seedlings, examining both their survival post-planting and their subsequent growth.
“I expose the trees to slightly more extreme climates than what we currently experience to predict their long-term response,” Schönbeck says. “The more we understand about their adaptability, the more confidently we can select suitable seedlings for the future.”
Schönbeck conducts her research at the Southern Swedish Forest Research Centre at the Swedish University of Agricultural Sciences (SLU).