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在福建洋口和江苏宜兴地区调查研究了3—23年生杉木树冠的形态结构。杉木的树冠外形随年龄阶段而变化,幼龄、壮龄时期树冠近似圆锥形,中龄时近似旋转抛物体形,成熟龄时近似圆台形。杉木年发生的枝盘数,决定于高生长;高生长旺盛期平均可发生5—6盘枝条。其分枝角度与枝条年龄有关,枝龄小的约55°—75°,枝龄大的可达90°以上。 杉木树冠长度与宽度随林木直径大小而变化,树冠的发育过程与密度密切相关。密度大的林分,阻碍树冠的发育,从而降低了林木的生长量,因此必须及时进行抚育间伐。 合理的树冠结构应该具有较大的有效树冠系数和叶面积密度。在高生长旺盛期,树冠层更新快,有效树冠系数高,叶面积密度大,利用空间的效率高,因而必须采取促进树高生长的营林措施,以改善树冠结构,提高杉木林的生产率。
The morphology and structure of 3 - 23-year-old Chinese fir canopy were investigated in Yangkou, Fujian and Yixing, Jiangsu Province. Cunninghamia lanceolata canopy shape with age and change, young, young crown period approximate conical, middle-aged approximate paraboloid rotation, mature age approximate truncated cone-shaped. Cunninghamia lanceolata occurs in the number of branches, determined by the high growth; high growth period can occur on average 5-6 branches. The branch angle is related to the branch age. The branch age is about 55 ° -75 °, and the branch age is up to 90 °. The length and width of the canopy vary with the diameter of the forest, and the development of the canopy is closely related to the density. Large stands of density hindered the development of the canopy, thereby reducing the growth of trees, it is necessary to conduct tending thinning. Reasonable canopy structure should have a larger effective crown coefficient and leaf area density. In the period of high growth, the crown canopy renews quickly, the effective crown coefficient is high, the density of leaf area is high, and the space utilization efficiency is high. Therefore, measures of silviculture promoting tree height growth must be taken to improve the canopy structure and improve the productivity of Chinese fir plantation.