Drivers of forest harvesting intensity patterns in Europe

Forests provide humankind with essential raw materials and the demand for these materials is increasing. Further expanding forestry into unmanaged forests is environmentally costly and increasing forest area via plantations will not immediately lead to increased wood supply. Thus, just like in agriculture, forestry faces the challenge how to intensify forest management in existing production forests in sustainable ways. Yet, our current understanding of what determines forest management intensity is weak, particularly at broad scales, and this makes it difficult to assess the environmental and social trade-offs of intensification. Here, we analyse spatial patterns of forest harvesting intensity as one indicator for forest management intensity across Europe, a region where most forests suitable for production are already in use and where future intensification is likely. To measure forest harvesting intensity, we related harvested timber volumes to net annual increment for the period 2000-2010. We used boosted regression trees to analyse the spatial determinants of forest harvesting intensity using a comprehensive set of biophysical and socioeconomic explanatory variables. Our results show that forest harvesting intensity varied markedly across Europe and harvested timber volumes were well below the increment in most regions. Harvesting intensity was especially high in southern Finland, southern Sweden, southwestern France, Switzerland, and the Czech Republic. The spatial patterns of forest harvesting intensity were well explained by forest-resource related variables (i.e., the share of plantation species, growing stock, forest cover), site conditions (i.e., topography, accessibility), and country-specific characteristics, whereas socioeconomic variables were less important. We also found the relationship between forest harvesting intensity and some of its predictors (e.g., share of plantation species, accessibility) to be strongly non-linear and characterised by thresholds. In summary, our study highlights candidate areas where potentials for sustainably intensifying timber production may exist. Our analyses of the spatial determinants of harvesting intensity also provides concrete starting points for developing measures targeted at increasing regional wood supply from forests or lowering harvest pressure in regions where forests are heavily used. Finally, our study emphasises the importance for systems' understanding for designing and implementing effective sustainable forest management policies. (C) 2014 Elsevier B.V. All rights reserved.