| 摘要: |
| 热带次生林面积巨大和在热带森林资源中越来越重要，因而拥有巨大的经营潜力和生态功能。次生林演替过程中的主要研究成果如下：土壤贮存的种子对次生林的再生非常重要，光投射的强度增加和温度提高将刺激种子萌芽，而残余植被群落强烈影响次生林种子的散布，食种子动物影响次生林的成林；次生林群落植物种类数量一般随演替的进程而增加；随着演替的进程，次生林内阳生树种趋于衰亡，耐荫树种不断增加；次生林的树种数量能接近原生林水平的时间过程更随着林分种类、过去土地的利用强度和利用种类，以及环境条件的不同而异；在一定环境中，人工林树种通过人工林树种改变光、温度和土壤表层的湿度，能够促进发芽和种子生长，改善林地的和林下植被的状况，从而加速次生林演替。大多数食草动物喜欢在次生林中取食，因为次生林中的先锋树种很少或没有机械和化学保护和林内许多树种产生大量可食用的果实；环境和火对次生林演替有一定影响；在早期的演替过程中，更多的生物量分配到资源需求旺盛的组织（如叶和细根），在演替晚期阶段，更多的生物量则分配到结构组织中（如木质部和根端）。次生林在15至20年内能迅速积累生物量，然后积累逐渐减慢；次生林被砍伐或火烧后，森林土壤的结构被破坏，导致土壤有机质和氮减少。 |
| 关键词: 热带森林 次生林 次生林经营 |
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| 基金项目:其它 |
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| Reference Analysis on Study of |
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He Boxiang
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| Abstract: |
| Tropical secondary forests own enormous potential and ecological function due to its vast area, and are an increasingly important component of the forest resources in the tropics. This paper reviews main research outcomes of secondary forests during their succession process. Soil-stored seeds significantly contribute to the development of secondary forests, increased levels of incident light temperature stimulate seed germination, whereas remnant vegetation and seed predator have strongly negative influence on the rate of initial colonization. Species and number of secondary forests generally increase with succession process. Early successional species are generally shade-intolerant while late successional species are shade-tolerant. Time frame that plant species richness in secondary forests approach old-growth values varies considerably depending on forest type, type and intensity of past land use, and environmental conditions. Artificial plantation can accelerate germination and growth of seed by improving the light, temperature and the degree of humidity of soil surface layer, so that they greatly accelerate processes of plant succession. Most herbivores feed in secondary forests because pioneer species in secondary forests do have little or no mechanical or chemical protection against herbivores and many early and late seral tree species in secondary forests produce edible fruits in large quantities. Environment and fire have some effects on secondary forest succession. In early succession, relatively more biomass is allocated to resource acquiring tissues (leaves and fine roots) and in later stages more is allocated towards structural materials (woody stems and coarse roots). The nutrient cycling of secondary forests is quick during approximately the first 15years of succession and it decreases as forests age. That the loss of soil organic matter and N due to deforestation and burning decreases soil fertility of secondary forests. |
| Key words: Tropical Forests Secondary Forests Management of Secondary Forests |
