Trade-offs in the multi-use potential of managed boreal forests.
Abstract
Implementing multi-use forest management to account for both commercial and non-commercial ecosystem services is gaining increased global recognition. Despite its spatial extent, and great economic and ecological values, few studies have evaluated the boreal forest and its management to assess the potential for simultaneous delivery of a suite of ecosystem services. Using data from a Swedish long-term experiment, this study explores how biodiversity of the ground vegetation and potential delivery of multiple ecosystem services (timber production, carbon [C] storage and non-timber forest products) are influenced by two common silvicultural practices (thinning, fertilization and their interaction). Diversity (diversity indices and species richness) of the ground vegetation was higher in thinned than in unthinned forest, a result attributable in part to six species of lichens that only occurred in thinned forest. In addition, supply of lichens for reindeer forage was three times higher in thinned forest. Fertilization negatively affected the lingonberry shrub (Vaccinium vitis-idaea). Timber production increased with fertilization, but decreased with thinning. The potential for C storage was highest in fertilized forests, which, apart from having the highest timber production, also supported the highest standing tree biomass. The silvicultural practices evaluated induced trade-offs among the ecosystem features studied as thinning increased biodiversity of the ground vegetation, production potential of wild berries and lichens, but reduced timber production and the potential for C storage. Fertilization had the opposite effect, promoting the potential for C storage at the expense of biodiversity and the ecosystem services delivered by the ground vegetation. Synthesis and applications. Increased multi-use potential is a common goal for forest management in many parts of the world. Our result shows that commonly used silvicultural practices can be used to determine the multi-use output, and might be applied to maintain, or even increase the multi-use potential of the boreal forest biome. Nevertheless, trade-offs among values were common, indicating that the multi-use potential will be limited at the site level. Allowing management objectives to vary across the landscape might, in such cases, be a preferable way to achieve high multi-use potential.