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杨树(POPUS SSP)是杨属的总称,属杨柳科,在植物分类学上,根据形态特征一般分为胡杨派,白杨派,黑杨派,青杨派,大叶杨派。而黑杨派具有重要的经济价值,全世界90%以上的栽培种都属黑杨。杨树原产北半球温带及寒温带森林之中,天然分布界限于北回归线(N23.5°)至北极圈线(N67.5°)之间,东半球平原地区的森林被砍伐改为农田之后,杨树便在河流两岸及旧河改道安家落户.到了十八世
Poplar (POPUS SSP) is a genus of Populus, belongs to the Department of willow, in plant taxonomy, according to morphological characteristics are generally divided into Populus, Poplar, Black Poplar, Populus, Populus. The black poplar school has an important economic value, more than 90% of the world’s cultivated species are black poplar. Among poplar native temperate and temperate temperate forests in the northern hemisphere, the natural distribution boundary is between the Tropic of Cancer (N23.5 °) and the Arctic Circle (N67.5 °). After the forests in the eastern hemisphere plain have been deforested to farmland, They settled on both sides of the river and the old river to settle in. To the eighteenth Century