( 5 ) since 3100 ab . r , through comprehensive analysis of these proxy climatic substitute indexes indicates : this was a dry and cold period in which the temperature fell the precipitation decreased ; the vegetation may be forest prairie ; human civilization further developed and the human " s influence on the environment was greater in intensity and wider in range 今，综合多气候代用指标和本期人类活动明显加强情况的分析表明：本期气候再次出现温度降低、降水量减少的变化，在趋于干冷气候条件下，在前期气候较适宜期发育的森林植被发生了退化，当时的植被可能为森林草原或干草原。
In this paper , we took the method of fuzzy evaluation to appraise the ecological environment quality of year 2003 in guangxi , the result indicated that the ecological environment quality was the between good and bad , and the industrial rubbish increasing and the forest vegetation decreasing were key factors undermining environment quality 摘要本文采用模糊综合评价方法对2003年广西生态环境质量进行了综合评价，结果表明广西生态环境质量为中等，处在好与差的临界状态；工业企业的废水、废气排放和森林植被减少是影响环境质量的关键因子。
The forest vegetation recovery payments shall be used for designated purposes ; the competent forestry authorities shall use them , according to relevant stipulations , for afforestation , recovery of forest vegetation ; the area of afforestation shall not be smaller than the area of forest vegetation reduced as a result of woodlands occupied or expropriated 森林植被恢复费专款专用，由林业主管部门依照有关规定统一安排植树造林，恢复森林植被，植树造林面积不得少于因占用、征用林地而减少的森林植被面积。
2 with the correlative analysis between the landuse structure and economic development , the main problems of landuse in youyang county are summarized as follows : ( l ) a large proportion of farmland are leanness , so the land quantity is bad ; ( 2 ) the forest vegetation is broken seriously , and the soil erosion is severe and the eco - environment is depravating ; ( 3 ) the number of land for water conservancy facilities is small ; ( 4 ) the proportion of town and transportation land is not accorded with landuse plan ; ( 5 ) land collocation is inconsequent ; ( 6 ) the land resources is plenty and a lot of land are not used but the land which can be opened up for farming 2通过对酉阳县土地利用现状结构与经济发展的相关分析，总结了酉阳县土地利用存在的主要问题有以下几点： ( 1 )中低产田比例大，土地质量差； ( 2 )森林植被破坏严重，水土流失严重，生态环境恶化； ( 3 )水利设施用地较少； ( 4 )城镇和交通建设用地欠账大( 5 )土地资源配置不合理； ( 6 )土地资源总量丰富，未利用地面积大，耕地后备资源不足。
Impacts of the project on vegetation , soil , and patterns of land use will influence the regional ecosystem . large area of cultivated lands , forests , shrubs , and other natural communities will be submerged when the project is built , which will inevitably result in loss of species diversity of plants and animals and their habitats . furthermore , climate may be changing because making of large area of water due to building of the dam 工程会对区域生态系统产生影响，其表现形式是通过对植被、土壤和土地利用格局的影响，影响区域自然生态体系的生态完整性；还会造成部分森林植被的淹没、野生动植物多样性及其生境的丧失、以及大面积水域形成后可能对当地一定区域内的气候产生影响。
Niche breadth of four dominate populations at three age groups was studied by the methods of resource utilization ability and ratio . the result shows that : symplocos sectchuanensis is a typical gengeration species whi ch resource utilization ability is strong , and distribution is wide . meanwhile , go rdonia acuminata , castanopsis fargesis and pinus massoniana specialized at some d egree in resource utilizationm , their distribution is limited . especially , the ju venile of pinus massoniana specialized outstandingly . with the devlopment of pinu s massoniana , which is the pioneer population in mt . jinyun , the environment become s unfit to it ' s juvenile . it turns to needle and evergreen broad - leaves mixed fo r est . because the tolerance toward shading of gordonia acuminata is lower than tha t of castanopsis fargesis , gordonia acuminata will be substituted by castanopsis fargesis and other evergreen broad - leaves species are the edificators . the popul ation ' s ability of resource utilization is the inner factor of population distri bution and community succession . the distribution of light and the concentrate of nutrient ( such as n ) is the outer factors of community succession 对缙云山森林植被的4个优势种群3个年龄级生态位宽度进行了研究.结果表明，川灰木利用资源的能力最强、分布广，为典型的泛化种.大头茶、栲树、马尾松对资源的利用在一定程度上特化，分布上有一定的局限性.马尾松的中龄组与幼龄组特化现象十分显著.缙云山森林植被的先锋种马尾松的发展，导致环境的改变不适于其幼龄个体的生长，群落演替到针阔叶混交林阶段，最后发展为以栲树等为建群种的常绿阔叶林.种群的资源利用能力，是种群分布与群落演替的内在原因，光因子和营养元素(如n )是群落演替的主要外部动力
