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加拿大杨速生丰产林的结构应着重研究杨林的配置方式和造林密度,因为它决定林木营养面积和叶面积的大小,从而影响林木的产量和质量。作者建议采用正三角形或正方形配置,提倡稀植,每公顷277—714株,或者先密后稀,早期疏开。确定造林密度的因子,首先是依据第一次间伐时平均树高、平均胸径与造林密度关系表”确定造林密度,同时试用冠幅的平方值,作为计算林木营养面积的依据;第二是依据土壤肥力(特别土壤水分)与经营强度确定造林密度;第三是依据苗木年龄及规格确定:造林密度。稀植加杨林,15年成林时,预计高达22米,胸径35厘米,每公顷木材蓄积量240—360立方米。
The structure of fast-growing and high-yield forest in Canada should focus on the configuration and planting density of Yanglin, because it determines the size of forest nutrient area and leaf area, thus affecting the yield and quality of forest. The authors suggest using a regular triangle or square configuration, advocating thinning, 277-714 plants per hectare, or dilute the first dense, early open. Determine the afforestation density factor, first of all is based on the first thinning average tree height, average DBH and afforestation density table "afforestation density, while trial crown square value, as the basis for calculating forest nutrient area; The second is based on Soil fertility (especially soil moisture) and management intensity to determine the density of afforestation; the third is based on seedling age and specifications to determine: afforestation density .Large planting plus Yang Lin, 15 years of forest, up to 22 meters, diameter 35 cm, Timber volume 240-360 cubic meters.