Spatial associations between tree regeneration and soil nutrient in secondary Picea forest in Guandi Mountains, Shanxi, China.

Abstract

According to the technical specifications of CTFS (Center for Tropical Forest Science), 190 sampling points of 4-hm2 plot (GDS plot) in Guandi Mountains of Shanxi Province, China were investigated to examine the spatial distribution pattern of seedlings and 14 soil indicators, including pH value and nutrient indicators. We analyzed the spatial associations between tree regeneration and soil nutrients, explored the mechanism of tree regeneration pattern of secon-dary Picea forest. The results showed that more seedlings survived in the patches with low contents of available N, available K, available Cu, available Fe, available Mn, available Ni and available Zn. Besides available K, the negative correlation between the other six soil nutrient factors and the number of regeneration seedlings of the Ⅱ (2.5 cm<GD≤4 cm) and Ⅲ (4 cm<GD≤5 cm) diameter classes with relatively large ground diameter (GD) was higher than that in the Ⅰ diameter class (0 cm<GD≤2.5 cm), indicating that soil nutrients had a greater influence on the distribution of regeneration seedlings in larger diameter class, and that the survival of regeneration seedlings was more dependent on soil condition. The soil of GDS was slightly acidic (5.5<pH<6.8). The increase of soil pH was accompanied by the decrease of available Al content, which was conducive to the regeneration and survival of trees. The total explanation of nine soil factors (including soil available N, available K, available Cu, available Fe, available Mn, available Ni, available Zn, available Al and pH value) on the regeneration and distribution of tree species in GDS plots was 19.7%.