Study on the Growth Effect of Cunninghamia lanceolata Clear-cutting to Renew C.lanceolata Schima superba Mixed Forest

For studying the growth effect，the clear-cutting renewal of C. lanceolata plantation at Yong’an national forest farm of Fujian were investiged. The results showed that 32-year-old artificial mixed forest of 8 C. lanceolata with 2 S. Superba，the average height，DBH and stand volume of C. lanceolata were 20. 1 m，25. 8 cm，0. 4727 m³，and stand stock was 425. 43 m³·hm^-2，which reached the growth index of large diameter wood in the most suitable area of C. lanceolata Ⅰ site class rapid growth and high yield forest. The average height (20. 5 m)，average DBH (26. 1 cm) and stand volume (0. 4923 m³) of C. lanceolata pure forest with the same stand age were decreased by 2. 0%，1. 2% and 4. 0%，respectively，but the difference between the two was not significant. Compared with the average height (18. 0 m)，average DBH (23. 6 cm)，stand volume (0. 3628 m³) and stand stock (392. 89 m³·hm^-2) of C. lanceolata pure forest (second goneration)，the average height 11. 7%，9. 3%，30. 3% and 8. 3% increased，respectively，and the difference between the two was extremely significant. The mixed forest of 8 C. anceolata and 2 S. superba (second generation forest) was beneficial to the cultivation of large-diameter wood of C. lanceolata，accounting for 51. 7%，which was 17. 0% higher than that of pure forest of C. lanceolata (second generation forest). It was a good model for the regeneration of the second generation of C. lanceolata forest to build the mixed forest of C. lanceolata and S. schima after the main clear-cutting of C. lanceolata.