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1.
长苞铁杉是我国特有的珍贵稀有树种,在赣南分布范围较窄,资源稀少。通过对上犹县境内五指峰长苞铁杉林的调查,分析其群落结构特征,对保护和发掘这一古老物种提出建议。  相似文献   

2.
In Cameroon, community forests are frequently presented as a relevant option to increase the welfare of rural populations and simultaneously improve local governance and forest resources conservation. But apart from community forests, rural livelihoods also depend on forest areas, designated as ‘domestic forests’ in this article, where local users enjoy informal customary rights. The specific contributions of community and domestic forests to the evolution of the prevailing socio-ecological system are assessed through a diachronic study of a village which is located in southern Cameroon. The Sustainable Livelihoods Framework is used to compare the progress of this social-ecological system between January 2008 and December 2009. The overall evolution of livelihoods was found to be positive during that period. In this case study, domestic forests and community forests are based on complementary models, which are often observed in southern Cameroon. Domestic forests constitute the basis of socio-economic development, while community forests might offer opportunities for a local-level carbon sequestration payment mechanism.  相似文献   

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随着我国新农村建设的推进,建材下乡政策的出炉,建筑业由大城市向小城市和农村发展,附属于建筑房地产行业的建材品种都将受益,同时亦给家具行业带来了机遇.对山东省齐河县新农村社区住宅橱柜市场进行深入调查,为建材、家具、橱柜企业进军乡镇农村市场提出相关建议.  相似文献   

5.
为了揭示蜘蛛群落在马尾松林中的地位和作用规律,于1995年4月至1996年6月对湖南新邵、长沙、岳阳3县不同立地条件马尾松林抽样调查90块样地.马尾松林蜘蛛群落计有25科62属107种.在马尾松林垂直分布的4个层次中蜘蛛群落具有明显的分层特征.灌木层的蜘蛛种类最丰富,林冠层次之.这两层蜘蛛对整个蜘蛛群落的稳定和控制害虫危害功能的发挥起决定作用,树干层和地面层蜘蛛处于过渡和补充地位.植被盖度对蜘蛛群落多样性和稳定性有显著影响,林龄的影响则不明显.  相似文献   

6.
利用组平均聚类方法,宜昌市公益林群落划分为8个群落类型,分别论述了各群落的结构特征.由种群的大小级结构动态和种群的存活曲线分析了各优势种群的结构格局,发现马尾松林、马尾松石栎林、柏木林、曼桐水丝梨林种群为下降种群.乌冈栎林、麻栎林种群为稳定种群,石栎樟树林、短柄枹栎化香林种群为增长种群.  相似文献   

7.
Many boreal tree stands are neither clearly even-aged nor clearly uneven-aged. The stands may undergo a series of stages, during which an even-aged stand is transformed into two-storied mixed stand, and finally to multistoried or uneven-aged stand structure. The species composition often changes during the succession of stand stages. This study developed models for stand dynamics that can be used in different stand structures and species compositions. The model set consists of species-specific individual-tree diameter increment and survival models, and models for ingrowth. Separate models were developed for Scots pine, Norway spruce, and hardwood species. The models were used in a growth simulator, to give illustrative examples on species influences and stand dynamics. Methods to simulate residual variation around diameter increment and ingrowth models are also presented. The results suggest that mixed stands are more productive than one-species stands. Spruce in particular benefits from an admixture of other species. Mixed species improve diameter increment, decrease mortality, and increase ingrowth. Pine is a more beneficial admixture than birch. Simulations showed that uneven-aged management of spruce forests is sustainable and productive, and even-aged conifer stands growing on medium sites can be converted into uneven-aged mixed stands by a series of strong high thinnings.  相似文献   

8.
记者从12月5日在广西桂林市召开的全国乡村绿化美化现场会上了解到,国家林业和草原局提出,要积极推进乡村绿化美化,以改善农村人居环境和促进农民增收致富为目标,以建设森林乡村为载体,紧紧围绕严格保护乡村自然生态系统的原真性、大面积增加乡村生态资源总量、大幅度提升乡村生态资源质量、大力发展乡村林草产业等重点任务,持续加大乡村绿化美化力度,努力打造生态宜居的美丽乡村。  相似文献   

9.
鹤山丘陵综合实验站是中国科学院华南植物研究所于1984年建立的.建站十几年来,退化生态系统得到了很好的恢复,植被状况良好,在该实验站生态系统恢复的初期,曾对该生态系统中的昆虫群落进行过研究(李健雄等,1995;谭炳林等,1997).为了更全面地反应目前该生态系统中昆虫群落的状况,更客观地评价该生态系统的功能,2002年对该生态系统中的昆虫群落的多样性进行了调查,曾对2002年10月的单次调查结果进行过报道(刘桂林等,2003;2005a;2005b),并比较了蝗虫、蜻蜓和蝴蝶3类昆虫的变化动态(刘桂林等,2008).本文重点报道了2002年各季节鹤山丘陵实验站4种人工林昆虫群落多样性的现状.  相似文献   

10.
几种人工杉木混交林土壤肥力对比分析   总被引:1,自引:0,他引:1  
通过对几种人工杉木混交林进行土壤物理和基本营养元素指标的测定和对比,结果表明:人工杉木混交林在改变土壤物理性质、改变土壤肥力等方面均优于杉木纯林,提倡合理营造杉木混交林。  相似文献   

11.
冰砬山天然次生林群落结构与物种多样性特征   总被引:3,自引:0,他引:3  
根据在辽宁冰砬山16块天然次生林样地的调查数据,对天然次生林的植物群落结构和物种多样性特征进行了研究,测定了各层次植物物种的重要值,采用多种方法计算各层次物种的丰富度指数、均匀度指数和多样性指数。结果表明:冰砬山天然次生林群落成层现象和各层次优势种比较明显,依重要值排序乔木层优势种为蒙古栎和紫椴,亚优势种为花曲柳、色木槭和怀槐;灌木层优势种为斑枝卫矛、金银忍冬、胡枝子和金刚鼠李,亚优势种为刺五加和胡榛子;草本层优势种为羊胡苔草。该地区天然次生林群落植物物种比较丰富,丰富度指数草本层最高,乔木层和灌木层较接近;均匀度指数和多样性指数灌木层最高,草本层最低,乔木层居中。  相似文献   

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13.
The leading question of this Forest Policy and Economics special issue is whether, how and to what extent forest governance processes can be better understood by means of discourse analysis and the science-policy interface. This article focuses on discourses only, but it does so from an institutional perspective. The reasons to advocate this so-called discursive-institutional approach are threefold: (1) to acknowledge the relevance of both meanings and rules in policy continuity and change; (2) to emphasize the role of ideas, concepts and narratives in institutional dynamics; and (3) to make a useful distinction between discourses and practices (‘analytical dualism’). As an example of applying this approach, we analyze the case of global forest politics from the early 1980s till today. It shows that new ideas and meanings concerning sustainability, biodiversity and governance have been institutionalized in this field over time, implying policy change and innovation. Compared to more ‘classical’ analyses, for example based on rationalistic or (purely) institutional accounts, the discursive-institutional approach draws another picture of global forest policy.  相似文献   

14.
以广东湛江特呈岛不同红海榄群落为研究对象,运用混交度、健康指数、大小比指数、竞争指数、角度尺和空间密度指数分析和比较了特呈岛不同红海榄群落空间结构。结果表明:群落2是高度混交,群落1和群落3属于中度混交,群落4为纯林;群落4红海榄纯林的胸径大小比最小,群落1红海榄和白骨壤混交群落的树高大小比数最小;林分空间分布格局中,所有群落的平均角尺度都大于0.517,为团状分布;红海榄、木榄混交群落健康状况比纯林群落好;红海榄纯林竞争指数最小,处于优势;群落3的平均空间密度指数比其它群落小,生长情况较好。  相似文献   

15.
对杉木、马尾松、木荷纯林及其习种不同的混交林分生物量和空间分布状况的调查分析,揭示混交林与生物量间的相互关系,以及生物量的空间分布规律,以便合理利用土壤、防止地力衰退,保持林业永续利用。  相似文献   

16.
Based on investigations during 1998–2003, shrubs and herbs, as well as indicators of similarity and diversity in Pinus tabulaeformis forests of ten regions around Beijing were compared and analyzed, and protection measures were suggested. Generally, the shrubs and herbs in P. tabulaeformis forests of Shidu, Mutianyu, and Yunfengshan are rich in species diversity and have great similarities. The percentages of common species in each of these three paired regions are above 50%, while many peculiar plant species that could not be found in the other nine regions exist in Labagoumen. As for plant diversity indices, plants in the P. tabulaeformis forests of Baihuashan, Shidu, and Labagoumen occur more frequently than in other regions, while the number of plants in Tanjiesi and Miaofengshan are far less. Some endangered orchid species were found distributed in P. tabulaeformis forests with a clumped spatial pattern but rarely appeared in other forest types, indicating that P. tabulaeformis forests are ideal habitats for orchid species. Translated from Journal of Beijing Forestry University, 2005, 27(4) (in Chinese)  相似文献   

17.
利用同体发酵方法,研究了黄山阔叶林和针叶林凋落物中的真菌对群落建群种甜槠和马尾松叶片的分解能力.在阔叶林和针叶林地真菌的分别作用下,75天后,甜槠叶片的平均失质量率分别是22.46%和22.45%,甜槠叶片的平均失质量率是马尾松针叶的1.5倍;两种树叶在分解前期(前45天)失质量率均显著高于后期(后30天).用阔叶林地中的真菌群落(KYJ)降解针叶和用针叶林地中的真菌群落(ZYJ)降解阔叶,发现KYJ的降解能力显著低于zYJ的降解能力,而对降解甜槠落叶而言ZYJ的降解能力则与KYJ相当,说明ZYJ具有较强的针叶分解能力,特别是降解木质素的能力.  相似文献   

18.
随着大面积规模化的种植,桉树人工林结构过于简单,林下植物多样性低的问题不容忽视。通过对普洱地区桉树人工林与同等条件下的天然林植物种类进行比较,桉树人工林群落物种数量流失,多样性下降和外来物种的入侵,说明一旦种植桉树以后,原有的生态系统都完全改变了,单一栽培桉树树种通常都造成了物种多样性的减少。  相似文献   

19.
分析了西双版纳山地雨林和季节雨林土壤节肢动物群落的组成、分布特征及多样性状况。 2块样地 2次取样 ,共获取大、中小型土壤节肢动物 6 6 0 6个 ,分属 2 3目。蜱螨目、鞘翅目、弹尾目、膜翅目仍是 2林地土壤节肢动物群落组成共有的优势类群 ,但它们在不同样地生境中构成的数量比例不同 ,而常见和稀有类群组成较为复杂且样地间的差异更为突出 ,总体表现出季节雨林具有更多的热带成分 ,山地雨林则界于热带和亚热带之间。土壤节肢动物类群总数、个体总数及重要生物类群 (个体数量在 10 0 0个·m- 2 以上 )的分布 ,表现为山地雨林 (2 2类 ,4 974个 )多于季节雨林 (19类 ,16 32个 ) ,垂直分布结果表明 2类林地均具明显的表聚现象。从多样性尺度看 ,山地雨林密度 -类群指数高于季节雨林 ,这与 2林地土壤条件的优劣相符合  相似文献   

20.
福建柏与香樟不同混交比例造林对比试验结果分析   总被引:3,自引:0,他引:3  
福建柏与香樟的不同混交比例、不同立地质量等级的造林对比试验结果表明,不同的混交比例,对福建柏、香樟的胸径和单株材积生长以及林分单位面积蓄积均有极显著影响,对福建柏树高生长的影响也达到极显著水平,但对香樟树高生长无明显影响。混交比例与立地质量等级的交互作用明显,应根据不同的立地质量等级选择不同的混交比例,Ⅰ、Ⅱ类地以7柏3樟最好,Ⅲ类地以7樟3柏为佳。  相似文献   

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