Convergent space–time tree regeneration patterns along an elevation gradient at high altitude in the Alps

In most mountain regions forests growing at high altitude have fundamental ecological roles and other benefits to humans. A key factor affecting the structure and evolution of these forest stands is the spatial and temporal dynamics of natural regeneration. Sound empirical knowledge is therefore important to support management prescriptions aimed at guaranteeing the space and time continuity of the forest cover through proper natural regeneration. By means of a spatial distribution and structure analysis in three 1-ha permanent plots along an elevation gradient at high altitude, we assessed the small-scale processes and interaction between canopy cover and regeneration establishment in a temperature limited environment. Particular attention has been paid to the interaction among three tree species (Larix decidua, Picea abies and Pinus cembra) and their specific regeneration behaviour. The spatial pattern of regeneration is very similar in all the tree stands in spite of the increasingly limiting environmental conditions with elevation and the significant differences at species and stand level. On the contrary, the small-clustered organization of individuals, typical of a high elevation area, only becomes visible at the highest sites considering the age spatial structure. Significant differences in stand structure, composition and history in addition to differences in species autoecology, mode and strategy of seed dispersal and growth are not enough to result in parallel differences in the distribution patterns of regeneration. Given that successful regeneration is one of the most significant bottlenecks for high elevation forest maintenance, any management approach should take this into account in order to better sustain the future stand structure and dynamics with likely future changes in environmental conditions. (C) 2013 Elsevier B.V. All rights reserved.