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密植的Ⅰ-69杨林分树冠分枝角度小,骨干枝比率低。当叶面积指数达到7.81、冠层最大叶面积密度达0.8～0.9时,是林分最适密度状态。光在冠层内的分布,受叶面积指数和叶片消光系数支配。密植的林分,光强衰减较快。以8%的相对光强作为临界光强,林龄6年时以高密度林分的生产能力最低;中密度林分最高。但林龄7年时,低密度林分的生产能力已经接近中密度林分。
Close planting Ⅰ-69 Yanglin points of branching branches of small, low rate of backbone branches. When the leaf area index reached 7.81, the canopy maximum leaf area density of 0.8 to 0.9, is the optimal stand density. The distribution of light within the canopy is governed by leaf area index and leaf extinction coefficient. Close planting, light intensity decay faster. With the relative light intensity of 8% as the critical light intensity, the productivity of high-density stand was the lowest when the stand was 6 years old and the highest was the middle-density stand. However, when the age of 7 years, the production capacity of low-density stands is close to the middle-density stands.