A STUDY ON THE DENSITY OF SEED TREE STAND OF PINUS YUNNANENSIS

Based on the experience of 3 intermediate cuttings in the seed tree stands of Pinus yunnanensis on Baimahe Forest Farm of Yongren County,it is concluded that the intermediate cuttings are a valid way and with characteristics of small investment,low cost and instant effect for the reconstruction of seed tree stand in the good stand of Pinus yunnanensis. Through the analyses in different ways,the authors find that the density of stand has a close correlation with its crown breadth.A table on the density monitoring for interme-diate cutting of seed tree stand of Pinus yunnanensis was drawn.With this table,the numbers of tree that should be cut can be determined and the crown breadth can be pre-dicted if the existing density and the numbers of seed trees are known.Meanwhile,mak-ing an experiment with 12 levels by studying the relationship between density and seed yield and summing up a formula for predicting the cone yield of a finalized seed tree stand,the authors proposed the optimum density for a finalized seed tree stand be 14锝18 trees per mu. All the work above provided a good method for setting up the seed tree stand of Pinus yunnanensis.