扬树是令世人瞩目的速生树种。但在一些早先发展杨树的国家,杨树的传统用途多已消失,木材销路不畅,市价持续不跌,遭到病虫危害或其他缺陷……,杨树的前途出现了疑问。法国人最初迷恋杨树、1946年共有杨树10.4万公顷,1964年发展到21.26万公顷,年均增长0.6万公顷;到1979年杨树总面积为25万公顷,年均增长0.25万公顷。后来 Poplar is a fast-growing tree that attracts worldwide attention. However, in some countries where poplar was earlier developed, the traditional uses of poplar have disappeared, lumber has been sold poorly, the market price has not dropped, pests and diseases have been endangered, or other defects have occurred. The poplar’s future has been in doubt. The French were initially infatuated with poplar trees. In 1946, there were altogether 104,000 hectares of poplar trees and 212600 hectares in 1964, an average annual increase of 6,000 hectares. By 1979, the total area of ​​poplar trees was 250,000 hectares, an average annual increase of 25,000 hectares. later