What defines a "healthy forest"? According to experts on the latest episode of IUFRO's "Branching Out" podcast, the answer depends entirely on your objectives. For a forest managed for timber, any insect or disease that reduces wood quality is a negative influence. However, in a native forest managed for biodiversity, these same agents can be beneficial, recycling nutrients and resetting the ecosystem.
In Episode 7, host Jose Bolaņos (IUFRO HQ) and co-host Raghav Sharma from the International Forestry Students' Association (IFSA) spoke with Tod Ramsfield (Natural Resources Canada/University of Alberta) and Maartje Klapwijk (Swedish University of Agricultural Science), Co-Coordinators of Division 7, Forest Health. They explained that their Division focuses on the interactions between trees and harmful biotic impacts, which are broadly divided into forest pathology (diseases, often caused by fungi) and forest entomology (insects).
Two of the biggest threats to forest health today are climate change and invasive species. Climate change alters weather patterns, creating stress like drought that makes trees more vulnerable to pathogens. It also makes new regions more hospitable for invasive species to establish themselves. These species often travel through global trade, not just in live plants but also hidden in wood packaging materials.
Managing these threats is complex. Strategies include planting mixed-species forests to "confuse" specialist insects, making it harder for them to find their host trees. For invasive pathogens affecting native ecosystems, like white pine blister rust in North America, scientists are working to breed resistant trees by identifying and propagating naturally resilient specimens. However, the best defence is often prevention, by keeping invasive species out of a country in the first place.
The conversation also highlighted the importance of interdisciplinary work, noting that managing forest health involves not only science but also legislation and understanding social attitudes.
Tune in to Branching Out: the forest podcast! Listen wherever you enjoy your podcasts, on Spotify and Apple Podcasts, and don't forget to follow us!
