dynamics and structure of natural regeneration in three high elevation lter area in the dolomites (north-eastern alps, italy)

Regeneration structures and spatial patterns of European larch (Larix decidua Miller), Swiss stone pine (Pinus cembra L.) and Norway spruce (Picea abies (L.) Karst.), were analyzed in three high elevation LTER area in the Dolomites (North-Eastern Alps). Larch and spruce regeneration is mainly affected by dense forest cover and grasses competition whereas stone pine is mostly sensitive to late snow melting, fungal diseases and wild ungulate damages. The current stand and regeneration structure suggests that larch has been highly fostered in the past due to silvo-pastoral management practices. All species show a clear tendency to spatial intraspecific aggregation especially at short-distances. The spatial patterns of larch regeneration are more complex than the other two species, more heavily affected by a main factor such as the nutcracker (Nucifraga caryocatactes L.) seed dispersal for stone pine or presence of canopy gaps for spruce. However, spatial patterns of all species depend on the number of the available microsites, that often match at small distance driving the formation of small mixed and unevenaged patches. Combining the age structure and spatial pattern information we were able to better understand the small-scale patterns and processes and the role of the past disturbances on the regeneration dynamics in space and time.