Natural regeneration of Sycamore maple in southern Sweden and Lithuania

Abstract: Sycamore maple (Acer pseudoplatanus) is a widespread but minor species in many central European countries. In Sweden and Lithuania it is non-native tree species, but natural distribution range is less than 100 km away in neighbouring countries. However here sycamore is able to regenerate and disperse to local forest stands. The aim of the study was to investigate sycamore regeneration in different forest stands and clearcuts adjacent to sycamore seed source stands. The study was conducted in southern Sweden and southwestern Lithuania. 30 sycamore source 48 adjacent stands of spruce, beech, oak, pine and clearcuts were selected for the survey. Results revealed that dominant tree species of adjacent stand and distance from a sycamore seed source were the most sycamore regeneration density influencing factors. The most suitable conditions for naturally regenerated sycamore were in oak stands. Sycamore regeneration was more abundant in the sample plots closer to the source stand and had a tendency to be influenced by prevailing winds. Seedlings in the height group lower than 0,5 m accounted for 98 % of all regeneration. Other investigated stands parameters: basal area, age, height, stand size, groundcover type did not have an influence on regeneration density.