人工造林与持续经营

中国造林与世界各地一样，纯林多，树种单调，因此发生的问题也相似。国内有识之士担忧，“前人栽树，后人遭殃”。国外同行也很重视我国关于杉木连栽使生产力递减的报道。包括德国在内的一些国家的造林实践却表明，纯林连栽并非必然减产。但造林树种单调与社会需求的多样性和环境立地条件的复杂性，确实构成了深刻的矛盾。如果不认真解决，人工林极难实现持续经营。

Man-made Forests and Sustainable Management

Achievements of afforestation in China are world famous.Now the area of man-made forests is 33.79 million ha,being about 1/4 of the world total.But with the upsurge of afforestation,some worrying events have occurred.The monoculture of even-aged pure stands with single species has caused the gradual decrease of stand growth,and leads to the loss of biological diversity jdisequilibrium of forest ecosystem and occurrence of disasters.The paper gives examples of some countries and regions where establishment of man-made pure forests with single species has raised troublesome prob-lems.The author believes that low productivity is one of important causes that speeds up the dwindling of tropical forests,and suggests that high yielding man-made forests are the requisite for sustainable forest management.