Path Analysis on the Crown Characteristics and Growth of Manglietia yuyuanensis in Mixed Stands

The correlation analysis on crown characterstics and individual volume growth of Manglietia yuyuanansis grown in 17-year-old mixed stand (Cunninghamia lanceolata× Manglietia yuyuanensis） was conducted. The results showed that the correlation coefficients betwwen individual volume index (D2H） and crown factors were different. Except single leaf area index (LAI） and crown layer density(CLD）, the total leaf area of single tree (TLA）,the tree crown area (TCA） and crown shape rate (CSR） were positively correlated to the individual volume index. The path analysis showed that TCA had the most direct effect on individual volume growth(Pyxi=1.201 3), which was the key factor affecting the individual volume growth of M.yuyuanensis, while TLA, CLD, CSR played their roles through TCA. The importance of the five crown factors above-mentioned on the individual volume growth of M.Yuyuanensis was in the order of TCALAIYLACSRCLD. It was found during analyzing the influence of crown spatial structure on individual volume growth that in vertical direction, the leaf area in middle and lower layers played decisive role to individual volume growth and the upper layer played less role:while in horizontal direction, the leaf area in the inner and outer parts contributed more to the individual volume growth and that in the middle part contributed less.