[Effects of topography on seedling regeneration in a mixed broadleaved-Korean pine forest in Xiaoxing'an Mountains, Northeast China].

To explore the responses of forest seedlings to topographic heterogeneity, nine hundreds of 4 m2 (2 m x 2 m) quadrats with perennial seedlings (H > or = 30 cm, DBH < 1 cm) were installed in a 9 hm2 plot in a typical mixed broadleaved-Korean pine forest in Xiaoxing' an Mountains. Based on the investigation data in 2006, 2008, and 2010, the effects of topography on the seedling establishment were studied. There were a total of 26 tree species in these quadrats. In 2006, 2008, and 2010, the total number of the tree seedlings was 4514, 6464, and 5611 individuals x hm(-2), respectively, among which, the seedlings of the top 10 species occupied >90% of the total. Topography had significant effects on the seedling distribution of the 8 major tree species. For Syringa reticulate var. mandshurica, Abies nephrolepis, Acer mono, Ulmus japonica, A. ukurunduense, Tilia amurensis, and A. tegmentosum, the spatial distribution of the seedlings was consistent with that of grown trees; but for Pinus koraiensis, the spatial distribution of seedlings was inconsistent with that of the grown trees. The mortality of S. reticulate var. mandshurica, A. nephrolepis, U. laciniata, A. tegmentosum, and T. amurensis seedlings was significantly correlated with the topography. The recruitment of S. reticulate var. mandshurica, U. japonica, P. koraiensis, A. nephrolepis, Fraxinus mandshurica, A. mono, and T. amurensis seedlings was also significantly correlated with the topography.