Effect of species composition on ecosystem services in European boreal forest

Forest management in several boreal countries is strongly focused on conifers because they are more productive, the technical quality of their stems is better, and their wood fibers are longer as compared to broadleaves. Favoring conifers in forest management leads to simple forest structures with low resilience and diversity. Such forests are risky in the face of climate change and fluctuating timber prices. Climate change increases the vitality of many forest pests and pathogens such as Heterobasidion spp. and Ips typographus L. which attack mainly spruce. Wind damages are also increasing because of a shorter period of frozen soil to provide a firm anchorage against storms. Wind-thrown trees serve as starting points for bark beetle outbreaks. Increasing the proportion of broadleaved species might alleviate some of these problems. This study predicts the long-term (150 years) consequences of current conifer-oriented forest management in two forest areas, and compared this management with silvicultural strategies that promote mixed forests and broadleaved species. The results show that, in the absence of damages, conifer-oriented forestry would lead to 5–10% higher timber yields and carbon sequestration. The somewhat lower carbon sequestration of broadleaved forests was counteracted by their higher albedo (reflectance). Mixed and broadleaf forests were better providers of recreational amenities. Species diversity was much higher in mixed stand and broadleaf-oriented silviculture at stand and forest levels. The analysis indicates that conifer-oriented forest management produces rather small and uncertain economic benefits at a high cost in resilience and diversity.