Study on the Relation of Tree Crown Indexes of E. urophylla and Thinning in Leizhou

Effective area of shining light on crown,crown ratio and projection area of crown of E.urophylla were studied in this paper.Three regression equations were built from three indexes and diameter at breast height(DBH).The results showed that the equation of effective area of shining light on crown and DBH had a positive effect on the breeding of the cultivation of middle-diameter plantation,the other equations were almost identical except for some differences between them.Tree number of stand and its base area per hectare offered a basis for E.urophylla plantation to thinning and afforestation.