Spatial distribution patterns and associations of typical tree species in different regions.

Abstract

Based on the monitoring data from the plots of Changbai Mountains in the temperate zone (CBS), Guandi Mountain in the warm temperate zone (GDS), Heishiding Mountain in the subtropical zone (HSD), we analyzed the spatial distribution of tree species from three families (Pinaceae, Fagaceae, Rosaceae) and their correlation using paired correlation function g(r). The results showed that the individual number and size class structural characteristics of the trees from the three families varied among different regions. Pinaceae had high population density and a bimodal size-class structure in GDS plot but a small number and skewed normal size-class structure in CBS and HSD plots. Fagaceae had low abundance and a bimodal, skewed normal size-class structure respectively in CBS and GDS plots but a large number and an inverted J-type diameter distribution in HSD plot. Rosaceae had high abundance and a L-type size structure in GDS plot but relatively low abundance and a L-inverted and J-type size class distribution respectively in HSD and CBS plots. The trees from those three families showed different spatial distribution patterns in three different forest plots. The large size class individuals of Pinaceae were regularly distributed at small scale in CBS and GDS plots but aggregated in HSD plot, the middle and small size class ones were consis-tently aggregated in three plots. Fagaceae trees were mainly characterized by large size class and approximately distributed at random in CBS plot, but mainly characterized by middle or small size class and aggregated in GDS and HSD plots. The trees of Rosaceae were aggregated in three plots. The aggregation degree of trees from three families decreased with the increases of spatial scales. The large size class individuals of Fagaceae were negatively associated at small scale or uncorrelated with Pinaceae trees in CBS and HSD plots. The middle or small size class individuals of Fagaceae were negatively associated with Pinaceae ones in CBS and GDS plots but positively associated with Pinaceae ones in HSD plot. Trees from Pinaceae were negatively correlated with trees from Rosaceae in three plots. The middle or small size class individuals of Fagaceae were positively correlated with individuals of Rosaceae in CBS and GDS plots but negatively correlated with trees of Rosaceae in HSD plot. In conclusion, the spatial distribution patterns and associations of the trees from three families changed with the size class, research scale and had different patterns among three plots.