造林密度,即单位面积上的栽植株数或立木的营养面积,是营造杨树人工林农业技术中最重要的因素。它在很大程度上决定着成林后的立木蓄积,不同材种的数量和质量。在苏联乌克兰,七十年代前杨树造林一直按2×1,2×2 m栽植,只是近年来的造林按2.5×2.5及3×3 m配置。各国根据其土壤、气候、杨树品种及栽培目的而采用不同造林密度。按照国际杨树委员会的材料(В.Д.Фплпмонова,1962;《林业和土地利用中的杨树》,1958),株行距0.5—4.0m(625—10000株/公顷)属于高密度,5—7 m(200—400 Afforestation density, that is, the number of plants planted per unit area or the stand area, is the most important factor in creating poplar plantations. It largely determines the accumulation of standing trees after the forest, the quantity and quality of different species. In the Soviet Union, Ukraine, poplar afforested by the 1970s has been planted at 2 × 1,2 × 2 m, only afforestation in recent years by 2.5 × 2.5 and 3 × 3 m configuration. Countries use different afforestation densities based on their soil, climate, poplar species and cultivation purposes. According to the International Poplar Commission’s material (В.Д.Фплпмонова, 1962; “Poplar in Forestry and Land Use”, 1958), plant spacing 0.5-4.0 m (625-10000 plants / ha) 7 m (200-400