Modelling the influence of thinning intensity and frequency on the future provision of ecosystem services in Mediterranean mountain pine forests

Abstract

Thinnings are silvicultural operations that repetitively reduce tree density to improve the vigour of the remaining trees and the economic benefits of the stands. Thinning can also enhance the provision of various ecosystem services throughout the rotation period. In this study, we use a modelling approach to evaluate stand dynamics and the provision of ecosystem services (mushroom production, wood for timber, carbon storage, blue water, and habitat for biodiversity) in Mediterranean mountain pine forests. We simulated thirteen thinning regimes—defined by intensity and frequency—under two different climate change scenarios. We implemented the thinning regimes using SORTIE-ND, an individual-based model of forest dynamics, and then we used models developed for the study area to calculate the provision of services. We used as a case study Pinus sylvestris and Pinus nigra stands, and we evaluated the effect of the thinning regime, climate change, and forest type over 100 years. Our simulations suggest that the production of timber and carbon decreased with increasing intensity and shortening frequency of thinnings, while the provision of mushrooms and blue water generally increased under those conditions. Large timber was better supported by a thinning regime with heavy intensity and shorter frequencies, which also favoured the rapid presence of large dead trees (dbh > 30 cm) in the stand. We found synergies between the production of timber and carbon, while the provision of mushrooms and particularly blue water were in a trade-off relationship with these services. Our simulations show that climate change will lower the production of ecosystem services under the most severe climate predictions and alter the effect of different regimes on the provision of services. We conclude that our modelling approach is a useful and efficient tool for answering questions that would otherwise require long-term studies, and that it can provide useful information to guide management efforts to adapt forest management to the challenges of climate change.