Long-time record of fire and open canopy in a high biodiversity forest in southeast Sweden Matts Lindbladh a, *, Mats Niklasson a , Sven G. Nilsson b a Southern Swedish Forest Research Centre, Swedish University of Agricultural Sciences (SLU), Box 49, 230 53 Alnarp, Sweden b Department of Ecology, University of Lund, Ecology Building, 223 62 Lund, Sweden Received 3 July 2002; received in revised form 8 January 2003; accepted 13 January 2003 Abstract We studied a ca 200 ha large forest site that holds an exceptionally large number of red-listed saproxylic beetles. We conducted pollen, charcoal and dendroecological analyses to reveal the long-term stand-level history of the site. We also investigated which of the red-listed saproxylic beetles recorded at the site are probably dependent on forest fires or structures that are created by fires. Pollen from Pinus and Betula dominate the pollen diagram, and the pollen record shows that the canopy is more closed today than ever during the last 2500 years. Large amounts of charcoal fragments were found throughout the core except during three shorter periods, one of which is the latest ca 200 years. The dendroecological investigation revealed 11 different fires, the earliest dated to AD 1586 and the last dated to AD 1868. Of the 105 red-listed saproxylic beetles recorded at the site, at least 12 are associated with open forests with Pinus sylvestris or Birch spp. trees. We conclude that the fires, as recorded both by the charcoal and den- droecological analysis, kept the site largely open in the past, and this is likely one important explanation for the high conservation value of the site today. Other important factors could be that the site is rich in boulders, the relatively warm summer climate in the region, that Picea abies has not been planted in the surroundings until recently, and finally the presence of many old trees. The study supports the theory that fire could have been an important factor for keeping some forest types open before the large human impact on the northwestern European forests started. # 2003 Elsevier Ltd. All rights reserved. Keywords: Charcoal analysis; Dendroecology; Forest conservation; Forest history; Pollen analysis; Saproxylic beetles 1. Introduction Many forest types depend on recurrent natural dis- turbances, e.g. fire, grazing by large herbivores, storms or high water levels. It is evident that ‘‘free develop- ment’’ is unsuitable for forest reserves where the pre- vious land-use kept the forest open, or where the natural disturbance regime is altered. ‘‘Free develop- ment’’ in these cases has created dense forests that are problematic for many of the species that were meant to be protected (e.g. Niklasson and Drakenberg, 2001). The degree of canopy openness is an important question in forest conservation in Europe (Vera, 2000; Nilsson et al., 2001; Svenning, 2002). This is particularly true for northern Europe, where the summers are relatively cool and where many species, e.g. saproxylic (wood depen- dent) beetles, depend on open conditions (Ga¨ rdenfors and Baranowski, 1992; Nilsson, 1992; Ranius and Jans- son, 2000; Martikainen, 2000; Nilsson et al., 2001), and in the Fennoscandinavian countries a high proportion of the saproxylic beetles are red-listed (Ga¨ rdenfors, 2000; Rassi et al., 2001). Hornso¨-Allgunnen is one of the most important areas in Sweden for this species group (Nilsson, 2001), and so far 218 red-listed saproxylic species have been recorded here (Nilsson and Huggert, 2001). The reasons for this high diversity, by far the highest known for any area in Sweden (Nilsson, 2001), are largely unclear. For instance, the stand structures or amount of dead wood are not strikingly different compared to forests in neighbouring areas. In this paper we study one site in the Hornso¨ -Allgunnen area in detail, Ska¨rsgo¨ larna (Fig. 1). This ca 200 ha large site holds the largest number of red-listed saproxylic beetles in the area: at 0006-3207/03/$ - see front matter # 2003 Elsevier Ltd. All rights reserved. doi:10.1016/S0006-3207(03)00043-0 Biological Conservation 114 (2003) 231–243 www.elsevier.com/locate/biocon * Corresponding author. Tel.: +46-40-415196; fax +46-40-462325. E-mail address: matts.lindbladh@ess.slu.se (M. Lindbladh).