Drivers of forest harvesting intensity patterns in Europe Christian Levers a,⇑ , Pieter J. Verkerk b , Daniel Müller a,c , Peter H. Verburg d , Van Butsic a,c , Pedro J. Leitão a , Marcus Lindner b , Tobias Kuemmerle a,e a Geography Department, Humboldt-Universität zu Berlin, Unter den Linden 6, 10099 Berlin, Germany b European Forest Institute, Sustainability and Climate Change Programme, Yliopistokatu 6, 80100 Joensuu, Finland c Leibniz Institute of Agricultural Development in Central and Eastern Europe (IAMO), Theodor-Lieser-Str. 2, 06120 Halle (Saale), Germany d Institute for Environmental Studies, VU University Amsterdam, De Boelelaan 1087, 1081 Amsterdam, The Netherlands e Earth System Analysis, Potsdam Institute for Climate Impact Research, Telegraphenberg A 31, 14473 Potsdam, Germany article info Article history: Received 1 November 2013 Received in revised form 19 December 2013 Accepted 23 December 2013 Keywords: Land use intensity Forest management Sustainable intensification Europe abstract Forests provide humankind with essential raw materials and the demand for these materials is increas- ing. 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 sustain- able ways. Yet, our current understanding of what determines forest management intensity is weak, par- ticularly 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 har- vested 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 bio- physical and socioeconomic explanatory variables. Our results show that forest harvesting intensity var- ied 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 socio- economic variables were less important. We also found the relationship between forest harvesting inten- sity 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 har- vesting 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 implement- ing effective sustainable forest management policies. Ó 2014 Elsevier B.V. All rights reserved. 1. Introduction Land use provides humanity with essential food, fibre, and bioenergy, but is also a major force of global environmental change (MA, 2005; Haberl et al., 2007; Pereira et al., 2010). As fertile land is getting scarce (Lambin and Meyfroidt, 2011) and further expansion of land use into remaining wildlands incurs high envi- ronmental costs, future production increases will, to a large extent, have to rely on sustainably intensifying land already in use (Foley et al., 2011; Tilman et al., 2011). Yet, assessing where future pro- duction can be increased and understanding the trade-offs of intensification is currently limited by incomplete knowledge about the spatial patterns and drivers of intensification pathways, espe- cially at broad geographic scales (Verburg et al., 2009; Erb, 2012; Lambin et al., 2001). This is particularly the case in forestry, where the spatial pat- terns of forest management intensity and the drivers that produce these patterns remain highly unclear. This is unfortunate, because 0378-1127/$ - see front matter Ó 2014 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.foreco.2013.12.030 ⇑ Corresponding author. Tel.: +49 (30) 2093 9341; fax: +49 (30) 2093 6848. E-mail addresses: christian.levers@geo.hu-berlin.de (C. Levers), hans.verkerk@ efi.int (P.J. Verkerk), mueller@iamo.de (D. Müller), peter.verburg@vu.nl (P.H. Verburg), vanbutsic@gmail.com (V. Butsic), p.leitao@geo.hu-berlin.de (P.J. Leitão), marcus.lindner@efi.int (M. Lindner), tobias.kuemmerle@geo.hu-berlin.de (T. Kuemmerle). Forest Ecology and Management 315 (2014) 160–172 Contents lists available at ScienceDirect Forest Ecology and Management journal homepage: www.elsevier.com/locate/foreco