Spatial distribution pattern of main tree species in Pinus tabulae formis forest of Heilihe in Inner-Mongolia.

A Pinus tabulaeformis forest which was established in Heilihe natural reserve of Inner Mongolia at the area of 1.96 hm2 were investigated by sampling methods.Tree composition and DBH structure of P.tabulaeformis forest were analyzed.Spatial pattern of main tree species in arbor layer and spatial distribution of P.tabulaeformis population on different growth stages(saplings,small trees and big trees) were analyzed by Ripley's K function.The results indicated that there were 13 tree species in arbor layer,and P.tabulaeformis was dominant species accompanied with Acer mono,Quercus mongolica,Tilia mongolica,Populus davidiana,Betula platyphylla as main concomitance species.DBH distribution of main tree species in P.tabulaeformis forest presented inverse J shape and showed some characters of natural forest.In spatial pattern,main tree species showed an aggregated distribution in the forest,among them,P.tabulaeformis showed an aggregated distribution at scale of 1~65 m and random distribution at scale of 65~70 m,other main tree species showed an aggregated distribution at all scales.Spatial pattern of P.tabulaeformis population tended to be random distribution with population growth(from saplings to small trees to big trees).