Seminar: Yimian Ma

Insect outbreaks are major disturbances in temperate forests, causing extensive tree mortality and significantly altering forest biogeochemical processes. Current climatic trends of increasing heatwaves and droughts in the European region exacerbate the frequency, intensity, and duration of insect outbreaks. In combination with other disturbances and climate extremes, insect outbreaks challenge the carbon sequestration potential of forests and introduce uncertainties in natural climate mitigation strategies. In this study, we examine the impacts of insect outbreaks on forest biogeochemical cycles by developing a new module for the QUINCY (Quantifying the effects of interacting nutrient cycles on terrestrial biosphere dynamics and their climate feedbacks) terrestrial biosphere model, focusing on two high-impact insect species: bark beetles and defoliators. We prescribed tree mortality or defoliation according to real events and simulated variations in carbon storage, greenhouse gas emissions, and nutrient transformations of Nitrogen and Phosphorus resulting from insect disturbances. Our study offers new tools and insights for evaluating the effects of insect outbreaks on forest biogeochemical functions. Based on these results, we advocate for attention to insect disturbances and improved forest management practices to mitigate the negative impacts of insect outbreaks in a changing climate.