A retrospective on 40 years shows that if we had accounted for these costs -- the cost of loss of topsoil, the cost of loss of waterways, the lost productivity, the loss to local communities desertification and so on -- those costs are almost twice as much as the market price of timber.
回顾过去40年， 我们可以看到，如果算上所有成本代价-- 包括表层土壤的流失、 河道的干涸， 以及由所有这些因素造成的 生产力减退、对当地社区的损害、 荒漠化等等问题-- 这些代价几乎是砍伐森林所得木材 市场价格的两倍。