Abstract
The non-native tree species Black Locust ((throughout Europe. So far, few studies have focused on their invasion into forests and none has addressed the influence of coppice management, which is characterized through regular clear-cuts. To retrace the invasion during the last 50 years, we studied the abundance in the canopy as well as the natural regeneration of these species in the coppice forest of Gargazon (South Tyrol, Northern Italy), which was ideal due to its patchy mosaic of different forest age (time since last coppicing). We analyzed which factors favor the presence and abundance of were sampled on 113 plots each measuring 7 m following environmental variables were recorded: canopy cover per species, total herb layer cover, distance to clearing, stone cover, slope, and aspect. Soil moisture was derived from herbaceous indicator species. Hurdle models were used for data analysis to account for the zero-inflated data structure. The results showed that altissima of both species synchronously to the coppice cycle, that means they colonize fresh clear-cuts, establish, and remain. We conclude that the currently applied coppice management, which consists of repeated clear cuttings each 20–30 years, favors the spread of both invasive species. Thus, an adaptation of the management system is needed to avoid further invasion. Robinia pseudoacacia L.) from N America and Tree of HeavenAilanthus altissima (Mill.) Swingle) from E Asia are invading both anthropogenic and near-natural habitatsA. altissima and R. pseudoacacia regeneration. Tree saplings2 in a total study area of 25.5 hectares. On each plot, theR. pseudoacacia has established earlier in the studied forest than A. altissima, but A.has been spreading with higher speed during the last 30 years. Our study exemplifies the invasion