关键词: 杉木, 造林密度, 生长进程, 经济分析

Abstract: The effects of planing density on the growth and economic benefit of Chinese fir were analysed by data of 15-year-old planting density trial stand，the results showed that planting density had the effect on the mean height of trees，but the difference was not significant．Diameter at breast height，single-tree volume，crown diameter alI decreased with the increase of density，the differ-ence among treatments was significance after 4 years．Both growing stock and height/diameter ratio increased with the increase of density，the difference in growing stock was significant from 7 to 12 years-old，but height/diameter ratio was not significant．Trees percentage of small logs increased with the increase of density，but trees and merchantable volume of large timber rapidly decreased．The peak of curve of trees distribution skewed to left．the peak move a diameter groups to left with　increasing a density class．By a synthetic analysis of growth increment，merchantable volume and e-conomic evaluation，the initial planting density was 1667 tree/hm²，which was considered as opti-mum．for cultivating large or middle diameter timber on a 18—20 site index．the density of 2500 tree/hm2 is also beneficial next to former one．

Key words: Chinese fir, Planting density, Growth process, Economic analysis