A recent international study has challenged the conventional wisdom that increased tree species diversity automatically enhances forest resilience to drought. Researchers at the University of Freiburg, in a collaborative effort, have found that the benefits of a diverse forest can diminish and even reverse, during prolonged periods of water scarcity.
The study, published in the journal “Global Change Biology”, analyzed the growth patterns of 1,600 trees representing 68 different species mixtures across Europe. While greater diversity has been shown to support tree growth during shorter, one-year drought periods, the findings reveal a more complex picture when considering longer, more severe droughts. Certain combinations of tree species may indeed improve drought tolerance, while others can lead to increased stress and competition for limited water resources.
According to Hernán Serrano-León, lead author of the study, the research underscores that higher tree species diversity shouldn’t be considered a universal solution for climate-resilient forests. He emphasized that the composition, rather than simply the number, of tree species will be a crucial factor in maintaining healthy and resilient forests, particularly in light of increasingly frequent and prolonged drought events. The study suggests a shift in approaches to forest management, focusing on targeted species selection and understanding the intricate interactions within forest ecosystems.