Journal of Vegetation Science && (2012) Sorbus aucuparia regeneration in a coarse-grained spruce forest – a landscape scale Magdalena Z ˙ ywiec, Jan Holeksa, Malgorzata Wesolowska, Janusz Szewczyk, Tomasz Zwijacz-Kozica & Pawel Kapusta Keywords Broad-leaved trees; Dispersal distance; Fleshy-fruited trees; Seedling and sapling bank; Stand mosaics; Sub-alpine spruce forest Nomenclature Mirek et al. (2002) Received 13 March 2012 Accepted 12 September 2012 Co-ordinating Editor: Hans Henrik Bruun Z ˙ ywiec, M. (corresponding author, m.zywiec@botany.pl), Holeksa, J. (j.holeksa@botany.pl) & Kapusta, P. (p.kapusta@botany.pl): Institute of Botany, Polish Academy of Sciences, ul. Lubicz 46, PL-31-512, Krako ´ w, Poland Wesolowska, M. (wesolowska.m@interia.pl): Institute of Environmental Protection, The Podhale State Higher Vocational School in Nowy Targ, ul. Kokoszko ´ w 71, PL-34-400, Nowy Targ, Poland Szewczyk, J. (rljszewc@cyf-kr.edu.pl): Forest Biodiversity Institute, Agricultural University, Al. 29 Listopada 46, PL-31-425, Krako ´ w, Poland Zwijacz-Kozica, T. (tzwijacz@tpn.pl): Tatra National Park, ul. Chalubin ´ skiego 42a, PL-34-500, Zakopane, Poland Abstract Questions: What is the spatial range of regeneration of the fleshy-fruited tree Sorbus aucuparia (rowan) in a coarse-grained spruce stand on a large landscape scale? Does the spatial distribution and size of stands of different ages affect the probability of rowan regeneration? What are the consequences of the dynamics of dominant coniferous tree species for the dynamics of admixture rowan? Location: A sub-alpine spruce forest in the Tatra Mountains, Poland. Methods: We mapped all mature rowans in a 203-ha area and counted the rowan seedlings and saplings on a grid of evenly distributed plots. In plots, the age and diameter of trees were measured. Patches of homogenous stands were distinguished and each rowan tree and each plot was assigned to one of four stand categories: dense small-crowned stands, dense large-crowned stands, sparse large-crowned stands and sparse stands near the upper forest limit. Areas above the upper forest limit formed a separate fifth category. Results: The distribution of rowan trees was clumped. Most of them grew in dense spruce stands up to 135 yr old and near the upper forest limit. Substan- tially fewer rowan trees were in sparse spruce stands of nearly 200 yr old. Seed- lings and saplings occurred at high density (mean 24.8 individuals 100 m 2 ) only up to 40 m from trees bearing fruits, and at much lower density at longer distances. In consequence of the clumped distribution of adult trees and the short range of seed dispersal, most of the old spruce stands were outside the range of abundant regeneration of rowan. Conclusions: The presence of fine- vs coarse-grained mosaics of coniferous stands of different ages can strongly influence population processes in a rowan population on a large landscape scale. Extensive disturbances resulting in large homogenous patches of coniferous stands, the long lifespan of a single genera- tion of spruce and spatial limitation of rowan seed dispersal seem responsible for the small contribution this broad-leaved species makes to sub-alpine forests. A high share of rowan can be expected in forests with fine-grained mosaics of stands, where small patches of young and old stands are inter-mixed, assuring delivery of seeds to stands of each category. Introduction Broad-leaved trees often constitute a small admixture in coniferous forests, both boreal and sub-alpine. In hemi- boreal and boreo-nemoral forests this group of species consists of Betula pendula, Betula pubescens, Populus tremula, Salix caprea and Sorbus aucuparia (Go ¨tmark et al. 2005; Vodde et al. 2010), while in European sub-alpine forests only B. pubescens and S. aucuparia occur frequently. Most broad-leaved trees that form admixtures in boreal and sub- alpine coniferous forests are shade-intolerant pioneers. High demand for light from the very beginning of growth, typical for these broad-leaved trees, results in their patchy distribution in coniferous forests. They benefit from distur- bances and establish mainly in canopy gaps. Sorbus aucuparia (rowan) has a special place among the broad-leaved trees growing in coniferous forests. It is a small tree or bush, shorter than birches and aspens. It is a Journal of Vegetation Science Doi: 10.1111/j.1654-1103.2012.01493.x © 2012 International Association for Vegetation Science 1