论文部分内容阅读
辽宁西、北地区风沙干旱,土壤瘠薄,树种单纯,植被覆盖率低,生态条件恶化,是我省水土流失重点地区。为了迅速恢复植被,改变生态环境,曾先后营造了大面积的杨树纯林,在防风固沙、保持水土方面,发挥了积极作用。但是,由于杨树生长量低,形成了“小老树”。如建平县惠州乡猞猁灰沟西北坡下腹,23年生的小叶杨林,平均树高2.67m,平均胸径2.43cm,已经显示出生长的不稳定性。因此,除应采取其它抚育改造措施外,更为经济有效的途径,则应注重营造混交林。
In the west and north of Liaoning Province, the wind and sand are arid, the soil is infertile, the species is pure, the vegetation coverage is low and the ecological conditions are deteriorating. It is the key area of soil and water loss in our province. In order to quickly restore vegetation and change the ecological environment, it has successively created a large area of poplar pure forest and played an active role in windbreak and sand fixation and soil and water conservation. However, due to the low growth of poplar, “small old tree” formed. For example, the 23-year-old Populus simonii Linn., With an average height of 2.67 m and an average breast diameter of 2.43 cm, has shown instability in growth. Therefore, apart from other measures for tending and reform, it should be more economical and effective to focus on the construction of mixed forests.