Analysis on the Growth Effect of Interplanting Castanopsis hystrix Under Large-diameter Wood Forest of Cunninghamia lanceolata

In October 2016, 30-year old-growth C.lanceolata large diameter timber stand was selected according to three reserve densities (A450, B600, C750 plants·hm^-2) in Fujian Yong'an State-owned Forest Farm.In February 2017, 825, 675, 525 plants·hm^-2 C.hystrix were interplanted accordingly reserve densities A、B、C three options, and in December 2021, age-complex forest scores were investigated.The results showed that the growth of C.lanceolata and C.hystrix increased with the increase of selective cutting intensity 5 years after interplanting, and there were significant or extremely significant differences in height, DBH, volume and volume of C.lanceolata and C.hystrix among different treatment combinations.The growth effect of the uneven-aged multi-layer forest formed by keeping 450 plants·hm^-2 of C.lanceolata and interplanting 825 plants·hm^-2 of C.hystrix is the best, with a total stand volume of 445.08 m³·hm^-2, in which the average tree height, DBH and individual volume of 35-year-old C.lanceolata are 27.20 m, 31.77 cm and 0.939 8 m³ respectively, which are higher than those of the control.The average tree height, DBH, crown width and volume of 6-year-old C.hystrix were 7.08 m, 6.26 cm, 3.52 m and 0.0123 m³, which reached the growth standard of suitable area for C.hystrix. The test results can provide a reference for cultivating high-value and high-quality large-diameter timberof C.lanceolata and C.hystrix timber.