近十多年来,黑龙江省营造了大面积的中东杨、小叶杨人工林,其中大部分已郁闭成林。随着林龄的增加,其立木材积也在不断的加大,而其营养面积则相应的缩小,致使各林分在生长过程中出现了明显的分化现象,其趋势也在日渐强烈。为了保证林木更好的生长,于1963年在龙江县绿色海洋林场的中东杨、 In the past decade or so, Heilongjiang Province has created a large area of ​​Poplar and Populus simonii plantations, most of which have closed forests. With the increase of forest age, the stand timber volume is also constantly increasing, while its nutrient area is correspondingly reduced, resulting in the growth of each forest there was a clear differentiation phenomenon, the trend is also growing. In order to ensure better growth of trees, in 1963 in Longjiang County, green ocean forest in the Middle East Yang,