Assessing impacts of intensified biomass removal on deadwood in European forests P.J. Verkerk *, M. Lindner, G. Zanchi 1 , S. Zudin European Forest Institute, Torikatu 34, 80100 Joensuu, Finland 1. Introduction Biodiversity is an important component of sustainable forest management, but assessing how ‘life in all its forms’ (Hunter, 1990) may change due to policy or management decisions is complicated. Indicators offer a practical solution (Hagan and Whitman, 2006) and the amount of deadwood has become a key indicator for forest biodiversity. Deadwood is particularly suitable, because it refers to resource availability and is positively correlated with species richness (Lonsdale et al., 2008) and as indicator it is applicable at a larger spatial level (Jonsell, 2007). Deadwood is an important food source and serves as habitat for many fungal, lichen and bryophyte, arthropod, mammal and bird species (Berg et al., 1994; Grove, 2002; Harmon et al., 1986; Heilmann-Clausen and Christensen, 2004; Jonsell et al., 1998; Jonsell et al., 2007; Lonsdale et al., 2008; Siitonen, 2001). In addition, variable types of deadwood offer a range of conditions for different saproxylic (i.e. deadwood-dependent) species with variable requirements. The type of deadwood is therefore also important and refers to properties such as whether deadwood is standing or lying, size-dimensions and tree species of deadwood. All these aspects determine the suitability of deadwood for different species or species assemblages (Berg et al., 1994; Grove, 2002; Harmon et al., 1986; Heilmann-Clausen and Christensen, 2004; Jonsell et al., 1998; Jonsell et al., 2007; Siitonen, 2001). In general, downed deadwood is more species rich than is standing deadwood (Berg et al., 1994; Franc, 2007; Heilmann-Clausen and Christensen, 2004), but some species or species assemblages are confined to standing or downed deadwood only (Franc, 2007; Harmon et al., 1986; Jonsell et al., 1998), indicating that both types are important deadwood types. Felling residues form yet another type important to many species (Jonsell et al., 2007). The size- dimension (diameter) of deadwood is also an important deadwood property, because different saproxylic species are confined to different size-dimensions (Grove, 2002; Heilmann-Clausen and Christensen, 2004). Ecological Indicators 11 (2011) 27–35 ARTICLE INFO Article history: Received 1 September 2008 Received in revised form 16 March 2009 Accepted 3 April 2009 Keywords: Biodiversity Bio-energy Deadwood EFISCEN Impact assessment ABSTRACT Deadwood is a key indicator for assessing policy and management impacts on forest biodiversity. We developed an approach to include deadwood in the large-scale European Forest Information Scenario (EFISCEN) model and analysed impacts of intensifying forest biomass removal on the amount and type of deadwood in forests of 24 European Union member states. In EFISCEN, deadwood consists of standing and downed deadwood, resulting from mortality, and stem residues from felling activities. To include deadwood in EFISCEN we developed mortality functions and re-estimated the model’s increment functions. Further, we modelled the development of standing deadwood. Decomposition of downed deadwood and stem residues was modelled through the soil model YASSO. We used the extended model to analyse the impacts of a baseline scenario (no policy changes, a moderate increase in wood removals and no extraction of residues) and a bio-energy scenario (an increase of wood and residue removals to the maximum potential) on deadwood in 2030. In our baseline scenario the average amount of deadwood was 12.3 ton ha 1 in 2005 and increased by 6.4% in 2030. Intensified biomass removal could fully counteract this development and lead to a reduction of 5.5% in 2030 below the levels in 2005. The type of deadwood changed as well; residue removal led to a general decrease in the amount of smaller deadwood fractions (i.e. stem residues). Further, if felling levels are increased as in our bio-energy scenario, a decrease can be expected in the amount of standing deadwood and of large-diameter deadwood. We conclude that without additional management measures to protect deadwood, intensification of biomass removal could negatively affect deadwood-dependent species, which constitute an important part of biodiversity in European forests. ß 2009 Elsevier Ltd. All rights reserved. * Corresponding author. Tel.: +358 10 773 4345; fax: +358 10 773 4377. E-mail address: hans.verkerk@efi.int (P.J. Verkerk). 1 Present address: Joanneum Research, Institute for Energy Research, Elisabeth- strasse 5, 8010 Graz, Austria. Contents lists available at ScienceDirect Ecological Indicators journal homepage: www.elsevier.com/locate/ecolind 1470-160X/$ – see front matter ß 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.ecolind.2009.04.004