Research on the Relationship Between Gap Characteristics of Cunninghamia lanceolata Plantations and the Growth of Gap Regeneration Phoebe bournei Seedlings

16 canopy gaps in Cunninghamia lanceolata plantations forest and preserving rate, ground diameter, and tree height of 3year old Phoebe bournei. plantation in mingxi, Fujian Province was investigated, and analyzed the effects of gap characteristics on planting regeration. The results showed that, in the order of affect on preservation rate and height growth of P. bournei. seedlings, the order of gap characteristics factors was canopy openness> gaps minor axis> gaps long axis > gap size. In order of affect on seedlings ground diameter, it was canopy openness> gaps minor axis> gap size > gaps long axis. There was a significant downward opening quadric parabolic relationship between canopy openness, gaps minor axis, gaps long axis, gap size and seedlings preservation rate, height， ground diameter. Comprehensive preservation rate, tree height and diameter growth performance, ideal gaps minor axis was range of 510 -626m, reasonable ranges was of 123-1013m. Ideal gaps long axis was range of 737 -788 m, reasonable was range of 344 -1181m. Ideal gap size was range of 150 -356m2, reasonable was range of 0 -8838m2. Ideal canopy openness was range of 0429-0507, reasonable was range of 0160-0776.