Structure and dynamics of a mature tree stand in submontane alluvial forest of Carici ramotae-Fraxinetum in the Sudety Mts foothills (Lower Silesia, Poland)

The structure andd ynamics of a submontane alluvial forest, with structural attributes of old-growth, in the Sudety Mts, Central Europe were examined. Stand structure was measured in circular sampling plots, and the distribution of gaps in belt transects. Past dynamic was reconstructed on the basis of analysis of events of release from suppression by inspection of growth pattern. The age distribution of canopy trees was also surveyed. The stand was dominated by ashes (Fraxinus excelsior) aged77–151 years, which created the upper layer, whereas the lower layer was dominated by dense hazel (Corylus avellana) shrubs. The analysedstandwas developedin site which was usedas a grasslandin first quarter of XIX century, but its history include several fine-scale disturbances when canopy trees were established. Recent dynamic was related to low intensity gap formation. The light conditions at the forest floor were good, and the average percentage of PPFD was 13%. Seedlings of ash and sycamore (Acer pseudoplatanus) were abundant throughout the stand. However, continuous browsing by game prevented growth of seedlings; in the sapling layer sycamore had disappeared and the number of ash saplings was strongly reduced. Regeneration was dominated by hazel of vegetative origin both in gaps and under the canopy.