最近几十年来，人类对森林的破坏到了加速的阶段，早在人类文明之初，地球陆地三分之二被森林所覆盖。随着人类文明的进步和人口的急剧膨胀，到十九世纪中期，全球森林面积由７６亿公顷左右减少到５６亿公顷，到二十世纪末期，这种趋势到了提速阶段，全球森林面积又迅速减少到 In recent decades, human destruction of forests have reached an accelerated stage. As early as the beginning of human civilization, two-thirds of Earth’s land was covered by forests. With the progress of human civilization and the dramatic population expansion, by the middle of the nineteenth century, the global forest area had been reduced from 7.6 billion hectares to 5.6 billion hectares. By the late twentieth century, this trend was accelerating and the global forest area rapidly Reduce to