Restoration of oak forests : soil charecteristics and light availability and their relation to early plant colonization patterns

Abstract: Recently established broadleaf plantations on former arable land initially do not contain a characteristic ground layer species community with forest herbs. They are therefore dependent on colonization processes. However due to former land use, environmental conditions in these plantations differ from continuously forested land. This study aimed to analyze some of the environmental conditions found in young secondary woodlands and investigates their importance forestablishment of ground layer species.Ground layer species communities of 36 broadleaf woodlands in Southern Sweden were analyzed in reference to their land use history. 18 recently established oak plantations on former arable land were compared to 18 adjacent old woodlands with long broadleaf forest continuity. Community ordination analysis was used to investigate the importance of differing environmental conditions between recentand old woodlands for the formation of the present ground layer species communities.Soil properties and light conditions were found to be significantly different between recent and old woodlands. In community ordination, the factor accounting for land use history was found to be most influential for the explanation of the observed differences in species community structures. However soil properties also seem to be an important factor influencing the colonization process.Even young plantations of 20 years in age can provide suitable growing conditions for typical forest species. However a precondition seems to be a high dispersalability of woodland species. Light and soil conditions in woodlands were found to be suitable to explain a large part of the variation in herb layer community structure. However further research is needed to be able to set the investigated factors in relation to other factors influencing the colonization process.