一般认为,形成商品树之前的林木疏伐,其经济效益以最终能否提高收获木材的经济价值来衡量.这种疏伐也许会减少单位面积上的木材收获总量,但可提高大中径材(以材积大于1/12立方呎为标准)产量.如果最终收获木材的等级和价格取决于疏伐后得到的大径材,那么疏伐就会使收入增多. It is generally accepted that the economic benefits of thinning forests prior to commodity tree formation are measured by the eventual improvement in the economic value of the harvested wood, which may reduce the total timber harvest per unit area but increase the size of large and medium If the grade and price of the final harvested timber depend on the large-diameter timber obtained after thinning, thinning will result in an increase in income.