长江中上游土壤资源保护与林业可持续发展

长江中上游地区土壤资源保护是一个关系到全局的重大问题，也是我国长江流域治理的关键，更是关系到当地人民生存和社会发展的根本性问题。从生态系统演替和土壤养分生物地球化学循环的角度出发，讨论了中上游地区林业生产及社会可持续发展的问题。

Protection of the Soil Resources in the Middle-Upper Stream Regions of Changjiang River for Sustained Development of Forestry

The great and disastrous flood in Changjiang River area,1998, caused extrmely heavy losses to the local people and the society. It was widely agreed that the extensive defforestation and serious soil erosion in the middle_upper stream regions of Changjiang River must be responsible for the flood, although the climate and low standard dams can not be excluded. As a significant reflection of the disastrous environmental destruction in the middle upper mountainous regions which were formerly covered by dense forests, attentions should not only be attracted to the flood itself but also to the harms of defforestation to the society and the ecosystem. Over_cutting, and unsuitable silvicultural measurements such as debris burning, complete site preparation and over_nursery were found the causes of so6il erosion, nutrient losses and biodiversity decline. This has deconstructed the foundation of forestry and local society, which is traditionally forestry_dependent. Biogeochemically, the washed out nutrient a Biodiversity nd soil minerals have to be re_accumulated by weathering of minerals and rocks geologically for the recovery of the fertility and functions of the ecosystems. In heavy eroded sites, the procedure of recovery is so long that the land became unutilizable before the predictable future. The protection of soil resources is critical to the sustainable development of this region by the following ways: thorough forbidding of debris burning, limited cutting amount according to the storage, artificial reform of the degraded forest stands into mixed ones, refforestation of bare mountains by suitable measurements, protection of natural forests for species expanding and biodiversity recovery.