三峡库区森林植被恢复与可持续经营研究

系统的野外调查数据和历史资料分析结果表明，三峡库区森林植被在空间上发展不均匀，无明显垂直分带，且分布分散，人为干扰严重。目前，在70多个植被类型中，森林类型占25个，江岸两侧海拔800 m以下地区森林已经很少。森林类型中，马尾松、柏木林的分布面积最大，并在许多疏林中成为主要树种，主要是飞播或人工种植。库区大于25°的坡耕地占耕地面积的17.5％。库区薪炭林仅能满足农村用能总需求量的10.78％。不合理的土地利用方式和对森林的不合理砍伐导致脆弱的土壤系统和森林生态系统的严重退化、生产力下降和严重的水土流失。库区土壤年侵蚀量达到2.9亿t。三峡工程建设和移民安置对库区森林生态系统的压力和影响将是长期的。调查结果同时表明，库区植物生物多样性丰富，植物种类在5 032种以上，而且乡土树种多。分析认为,只要抓住三峡工程建设的契机，紧密结合国家天然林保护和退耕还林工程建设，充分利用良好的生物学基础，科学地封山育林，分带逐步恢复，同时，因地制宜，退耕还林，发展森林能源，建设多目标复合和多种模式并存的林业经营体系，发展经济，就能从根本上改善森林经营环境，实现森林恢复，形成合理布局的水库森林防护系统，促进三峡库区生态环境建设和可持续发展。

SPATIAL DISTRIBUTION, DISTURBANCE AND RESTORATION OF FORESTS IN THE THREE GORGES RESERVOIR REGION

Based on the analysis of survey and literature, the paper shows the vegetation in the Three Gorges Reservoir Region is of sparse and uneven with unclear vertical distribution and is disturbed seriously by human activities. Among the 75 vegetation types there are 25 forest types. At present, there is little distribution of forest below the elevation of 800 m. The Pinus massoniana and Biota orientalis occupy the largest area in the region, and are also the main forest species in the sparse forest grown by aero-sow and artificial planting. The cultivated land on the slope above 25 degrees accounted for 17.5% of total cultivated land. The firewood forest offers only 10.78% of total energy in the countryside. Irrational land use and forest cutting have resulted in the serious degradation, the decrease of land productivity and the water and soil erosion in the fragile soil system and forest system. The soil erosion volume is up to 290 million tons per year. The effects of the Three Gorges engineering construction and large-scale population migration on the forest systems are of long-term. The paper also shows that there are rich plant species diversity in the Three Gorges Reservoir Region. The plant species are at least up to 5 032 with the rich native species. In combination with the key forestry programmes such as Natural Forest Conservation Program and Land Conversion Program in the middle and upper reaches of the Yangtze River and other forest restoration actions, such as closing the mountain for raising forest, returning the cultivated land on the slopes above 25 degrees to forest, developing the firewood for energy and building the forestry management system with the multiple functions and mixed management models, the forest management environment will be improved to restore the forest efficiently. This is important for the reservoir forests shelter system and will promote the ecological and environmental construction and sustainable development in the region.