Abstract:

Acacia mangium is a typical and important exotic tree species for short_rotation industrial plantation in south China. It was found that the species could naturally regenerate from seed at appropriate site conditions. The seed of A. mangium in plantations could germinate only in open areas in stand edge. The longest dispersal distance of a single-tree at age of 16 years was 17.5 m and the largest number of regenerated trees was 26 in a 45° sector area around the tree. The distance of single-tree dispersal was not closely related to the number of regenerated trees. The longest distance of dispersal from stand edge of A. mangium was 10.0 m, which were planted with roots buried in hole in 1987, and the largest number of regenerated trees was 3. The longest distance of dispersal from stand edge of A. mangium was 3.0 m for the other stand planted in 1997, and the largest number of regenerated trees was 14. The effects on natural regeneration of native trees, shrubs and herbaceous plants under the A. mangium plantation were surveyed by setting sub-plots within the sample plots. 12 native tree species, 3 shrub species and 8 herbaceous plants species were found. They all have strong viability under the A. mangium canopy. Results indicated that A. mangium can naturally regenerate from seeds and establish itself in open areas in the stands. No significant impact on native tree species and other vegetation was found, indicating that the risk of bioinvasion of A. mangium is low.

Key words: exotic tree, Acacia mangium, natural regeneration