Response Of Forest Seedlings And Shrubs Regeneration To Topographic Heterogeneity In A Mixed Broadleaved-Korean Pine(Pinus Koraiensis)Forest In Xiaoxing’an Mountains

To explore the response of forest seedlings and shrubs to topographic heterogeneity,900perennial quadrats at4m2(2m×2m) were set up in a9hm2plot in a typical mixed broadleaved-Korean pine forest in Xiaoxing’an Mountains. All seedlings and shrubs ((H)≥30cm, DBH<1cm) in the quadrats were tagged, measured, and identified according to species. Based on censuses in2006,2008, and2010, we found that a total of26tree species and and18shrubs species could be recorded in these quadrats. Approximately4514,6463, and5611seedlings·hm-2were found in2006,2008, and2010, respectively. The top10species comprised90%of these seedlings. Three years the total number of shrubs were18253-hm"2,27383·hm-2and23300-hm-2, of which the top ten shrubs comprised of99%. The topography significantly affected the seedling distribution of the8major tree species (p<0.05). For Syringa reticulate var. mandshurica, Abies nephrolepis, Tilia amurensis, Acer tegmentosum, A. mono, Ulmus japonica, and A. ukurunduense, seedling distribution was significantly affected by topography and was consistent with the distribution of grown trees. The seedling distributions of Pinus koraiensis was inconsistent with that of the corresponding grown trees. The mortality of S. reticulate var. mandshurica, A. nephrolepis, U. laciniata, A. tegmentosum, and T. amurensis seedlings significantly correlated with the topography (p<0.05). Furthermore, the recruitment of S. reticulate var. mandshurica, U. japonica, P. koraiensis, A. nephrolepis, Fraxinus mandshurica, A. mono, and T. amurensis seedlings significantly correlated with the topography (p<0.05). The topography significantly influenced the distribution, mortality and recruitment of Acanthopanax senticosus, Ribes mandschuricum. Philadelphus schrenkii, Deutzia gladata, Lonicera chrysantha, Euonymus pauciflorus, Spiraea salicifolia, Corylus mandshurica, L. praeflorens and Sorbaria sorbifolia the10major shrubs(p <0.05).