角倍蚜人工繁殖技术的效益分析

角倍蚜人工繁殖技术的效益分析王健，傅小川关键词角倍蚜，五倍子，经济效益角倍是主要的五倍子种类之一，质量好、分布面积大，占五倍子总产量的７５％。遵义是五倍子的最佳产区，历史上最高年产曾达到５０００余ｔ．自１９８２年以来，年产仅有５００余ｔ，且处于野生野...     

秭归县退耕还林水源涵养效益计量

林地是森林水源涵养效益的主体,通过对秭归县10种退耕还林模式的土壤物理性状和林地水源涵养效益的研究,结果表明:(1)退耕还林后土壤总孔隙度增加4·3%~20·2%,除柏木林外,非毛管孔隙度增加6·8%~494·2%;(2)退耕还林后土壤饱和蓄水量增加5·7%~118·8%,非毛管蓄水量为坡耕地的2·58~19·13倍;(3)秭归县退耕还林森林土壤的蓄水量为171·6万m3/a,是相似立地条件下农耕地的3·21倍。     

宜昌公益林可持续经营条件与对策

在分析宜昌公益林可持续经营的制约因素与有利条件的基础上,依据公益林营造的基本原则,阐明了公益林营造途径和营造方法;同时以公益林恢复重建途径为指导,提出公益林恢复重建模式;并依照公益林保护原则,探索了宜昌公益林保护的基本思路,对宜昌公益林可持续经营具有现实指导意义。     

长白落叶松丰产林造林密度及其经济效益初探

本文以长白山落叶松人工林的造林初植密度为研究对象,在5种不同初植密度下,优选出适于黑龙江省利用世界银行贷款集约经营人工林项目合理密度。建筑材林分的合理初植密度为3000株/ha,纤维材林分为3300株/ha。     

林带阻力与透风系数关系的试验研究

利用多年的疏透度、透风系数的野外观测和风洞试验资料,给出了立体结构林带和平面结构模型林带疏透度和透风系数的关系式分别为α=β~(0.4)及α=β~(0.95)。利用台式天平测定了7种风洞模型林带的阻力,以透风系数表示林带结构,阻力为C_α=16.3(1-α)~(0.55),以疏透度表示林带结构,阻力系数为C_β=14.0。     

Foresters' beliefs about farmers: a priority for social science research in social forestry

This study suggests that one of the most productive (and most neglected) uses of social science research in forestry development projects is to examine foresters' beliefs regarding rural peoples. This suggestion is illustrated with data from the Forestry Planning and Development Project, Pakistan's first nation-wide social forestry project.The operational component of this project, intended to assist small farmers to cultivate trees on their farmlands, ran into immediate difficulties. Many of the foresters involved insisted that small farmers were simply not interested in tree cultivation. A comprehensive base-line study subsequently was carried out to examine the validity of this belief. The results of this study (confirmed by the subsequent experience with the project in the field) varied markedly from the foresters' beliefs.While many of the foresters believed small farmers were opposed to having trees on their farms and would not agree to plant trees under the project, most farmers already had trees on their farms and expressed interest in planting more; while many foresters believed farmers would only be interested in planting large blocks of market-oriented exotics, most farmers requested small plantings of multi-purpose native trees; while many foresters believed farmers would plant trees only for market sale, most farmers requested trees to meet household needs for fuel and timber; and while many foresters did not think that increasing supplies of fuelwood could reduce the burning of dung, all of the evidence provided by the farmers suggested that it would.The disparity between farmer reality and forester belief is attributed to failures on the part of both foresters and social scientists — failure by foresters to distinguish their non-empirical beliefs about farmers from their empirically-based knowledge of trees, and failure by social scientists to recognize the belief systems of foresters as a legitimate and important object of study. Their study comprises three parts: finding out what the foresters think the farmers want, finding out from the farmers what they actually want, and then analyzing and explaining the differences.     

中国大规模造林减少大气碳积累的潜力及其成本效益分析

在对中国森林实行永续轮伐的假定下，计算了通过大规模造林来减少大气中ＣＯ２积累的潜力，并进行相应的成本－效益分析。首先把中国分成５个区，在每个区中选择４种造林或森林经营的方式，总计２０种造林或森林经营的方式，根据现有可用于造林的土地面积的资料，对这些造成林或森林经营的方式进行计算。     

麻竹笋用林高效可持续经营技术

以麻竹笋用林高效栽培为目标，可持续经营为原则，总结了竹林林分结构调控、土壤管理、散生状培育、地理种源和无性系选优等操作简便、应用效果好的系列实用技术，分析了目前麻竹林立地生产力退化、产品产量和质量下降等的主要原由，提出了无害化、品种化和散生状培育的经营方向。     

湖北宜昌公益林可持续经营能力的数量化评价

论述了宜昌公益林可持续经营数量化评价的指导思想和基本原则,并以公益林可持续经营的基本要素为依据,建立了综合评价指标变量集;通过主成分分析和层次分析,提取了累计贡献率大于81%的11个指标因子,确定了各指标因子的权重;从发展规模总量和结构协调度两方面对公益林可持续经营能力进行了评价,认为宜昌公益林的发展规模不断扩大,但其结构协调度DHT=0.722,协调能力较差,仍处于弱可持续发展阶段.     

浅析完善中国森林生态效益补偿制度

随着地球人口的增加和人类活动的加剧,保护森林资源已经提上了各国的议事日程。而对于我国这样的一个贫林国家,森林资源的保护问题与森林生态效益的补偿就显得愈加迫切与重要。文章针对我国现有的森林生态效益补偿制度的沿革、存在的问题进行了分析,并提出我国森林生态效益补偿制度需进一步完善或创新。