Tree regeneration before and after restoration treatments in managed boreal Picea abies stands de Chantal, M. 1,2 ; Lilja-Rothsten, S. 1,2,3 ; Peterson, C. 4 ; Kuuluvainen, T. 1,5 ; Vanha-Majamaa, I. 2,6 & Puttonen, P. 2,7 1 Department of Forest Ecology, PO Box 27, FI-00014 University of Helsinki, Finland; 2 Finnish Forest Research Institute, PO Box 18, FI-01301 Vantaa, Finland; 3 E-mail saara.lilja@helsinki.fi; 4 Department of Plant Biology, University of Georgia, Athens, GA 30602-7271, USA; E-mail chris@plantbio.uga.edu; 5 E-mail timo.kuuluvainen@helsinki.fi; 6 E-mail ilkka.vanha-majamaa@metla.fi; 7 E-mail pasi.puttonen@metla.fi; Corresponding author; Fax 1358-10-211 2203; E-mail michelle.dechantal@helsinki.fi Abstract Questions: What are the short-term effects of restoration treatments, including fire and/or partial cutting with dead wood creation, on seedling density and distribution among microsites, and do they differ between upland and paludified biotopes? Location: Mature managed Picea abies-dominated stands in southern Finland. Methods: The restoration treatments consisted of four levels of cutting, with and without fire: uncut, low-CWD (partial cutting leaving 50 m 3 ha  1 of standing retention trees and 5m 3 ha  1 of down retention trees, DRT), intermediate- CWD (as previous but with 30 m 3 ha  1 of DRT), and high- CWD (as previous but with 60 m 3 ha  1 of DRT). Results: The cutting treatment alone did not affect seed- ling density. Fire had an immediate effect, both by itself in upland biotopes (decreasing effect on P. abies density) and in combination with cutting in paludified biotopes (in- creasing effect on Betula spp. density). The density of other deciduous species (Sorbus aucuparia, Populus tremu- la, and Salix spp.) was not affected. Before treatments, seedlings grew predominantly on level ground and mounds. After treatments, more Betula, but fewer P. abies and other deciduous species, grew on these microsites. More Betula and other deciduous species grew next to CWD and under a fallen crown; more P. abies grew under a fallen crown in unburned stands. Conclusion: The post-treatment tree seedling density and distribution among microsites can be affected by restora- tion treatments. However, knowledge of local site characteristics and their interaction with different restora- tion treatments is needed to achieve the goals set for restoration at the stand and landscape levels. Keywords: Coarse Woody Debris (CWD); Disturbance Dynamics; Managed Forest; Microsites; Seedling Density; Seedling Distribution. Abbreviations: CWD 5 Coarse Woody Debris; DRT 5 Down Retention Trees; SRT 5 Standing Retention Trees. Introduction During post-disturbance regeneration, the suc- cessful recruitment of new seedling cohorts often crucially depends on the availability of suitable mi- crosites (e.g. Harper et al. 1965; Brang 1997; Simard et al. 1998). Microsites can be defined as local features of the forest floor, at a scale of tens of centimeters, which characterise the seedling’s growing environment, such as substrate type or microclimate. Natural disturbances create microsite legacies such as logs and stumps, and affect micro- topography, thereby altering post-disturbance seedling distribution among microsites (Sire´ n 1955; Hytteborn et al. 1987; Nakashizuka 1989; Ho¨ rnberg et al. 1995; Lee & Sturgess 2001). For instance, the elevated microsite structure provided by large dia- meter logs and stumps may protect seedlings from flooding in paludified areas (Ho¨rnberg et al. 1997) and offer a reduced competition environment due to sparser vegetation (Harmon & Franklin 1989; Nakashizuka 1989; Peterson et al. 1990). Alter- natively, dead wood aggregations and treefall root mounds may provide refugia from ungulate brows- ing (Long et al. 1998; Ripple & Larsen 2001; Applied Vegetation Science 12: 131–143, 2009 & 2009 International Association for Vegetation Science 131