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泸西县为云南省石漠化程度较高的区域之一,属喀斯特地貌.为了掌握泸西县林地及天然林资源特征,以泸西县2019年森林资源监测数据为基础,从土地利用、林地类型、优势树种及林地管理属性等方面进行了分析,为该区域森林资源保护、监测及相关规划提供依据.结果表明:泸西县林地面积占比较低,仅占国土面积的47.16％,森林覆盖率偏低,仅... 相似文献
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上海林地和绿地的土壤碳含量较低,固碳能力约为7.5万t/年。通过植树造林增加碳汇的潜力有限。建议通过加强森林抚育提高森林碳储量和碳密度;探索多元化的城市林业建设方式;因地制宜发展立体绿化,提高城市绿量;实施节约型园林绿化管理模式等措施来提高碳存储能力。
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一个生态系统在最优良条件下的生产力被称作生产潜力。文章采用现实森林生产力级数和期望森林生产力级数评价广东省林地生产力。广东省约6成县（市、区）的现实森林生产力级数低于25,期望森林生产力级数高于25。韶关市始兴县现实森林生产力级数和期望森林生产力级数都是最高的,分别为41和45;广州市荔湾区、越秀区、海珠区和佛山市禅城区现实森林生产力级数和期望森林生产力级数都为0。频数分析表明,现实森林生产力级数在[5,10）区间的县（市、区）最多,共27个;期望森林生产力级数在[40,45）区间的县（市、区）最多,共36个。通过林地生产潜力聚类分析,全省可分为5个类型的区域。重点描述各个类型的主要特征,为区域性林业生产力布局调整和森林经营提供科学依据。 相似文献
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Input/output data from tree growing experiments in Southeast Asia were analysed within the framework of a model of a smallholder farm. Data on cropping were obtained from surveys of farmers. Prior to formulating a whole farm model, this input/output data were modified in two ways: (a) a yield penalty was imposed upon a continuous cropping regime to reflect the impact of land degradation; (b) an agroforestry (intercropping) activity was synthesised by reference to an existing agroforestry bioeconomic model. The modelling framework was conventional linear programming. The interplay of land area availability, land and labour productivity, and interest rates lead to a relatively complex picture, even for the simplified farming systems that were examined. Model results showed a clear indication of the potential role of trees, but this potential role decreased with increasing interest rates. The analysis suggested that smaller farms will be less inclined towards tree growing. A mixture of trees and crops appears attractive, on purely economic grounds, over a wide range of interest rates and land areas. Consideration of factors outside the model, such as risk aversion objectives of smallholders, and their limited opportunities to borrow for investments in tree planting, reinforce the tendency to combine trees and crops. 相似文献
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以“九五”攻关课题“嫩江沙地治理技术与示范”在泰来县建设的治理开发区工程为基点 ,对示范工程建设前后及建设区内、外的生态因子进行对比观测调查 ,利用主成分分析、关联分析、主分量分析等方法将收集到的生态因子进行筛选 ,提出嫩江沙地风蚀荒漠化生态环境变化的主要生态因子指标 ;以土地生产力为应变量 ,以生态环境因子变化引起土地生产力变化的主导生态因子为自变量 ,进行逐步回归分析 ,建立环境质量变化的评价指标体系和定量化评价公式。经计算半固定沙丘治理开发及庄园式沙地治理开发的评价值分别为 2 .0 2 32和 2 .32 4 5 ,均大于优化值 1.5。 相似文献
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丽水地区林地资源市场配置问题的初步探讨 总被引：2，自引：1，他引：1
林地资源是森林资源的重要组成部分，市场经济的发展需要正视林地资源的市场配置问题。本文在介绍丽水地区林地资源流转的历史、规模与结构、双方属性及程序等基本情况的基础上，就林地便条以流转评价中的问题及其原因进行分析，并提出了加强友观调控若干政策的建议。 相似文献
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巴林左旗现有的森林资源的林分质量不高,但林地生产力的潜力较大,要把提高林地生产力定为巴林左旗发展森林资源的主攻方向之一,把培育发展和保护森林资源做为林业工作的中心任务,坚持以保护森林资源为前提,以培育发展森林资源为中心,走保护与培育发展并重的道路。文章对该旗的林业生态系统进行分析,并针对该旗森林资源培育中的一些问题提出了建设规划建议。 相似文献
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Tree planting on deforested farmlands, Sewu Hills, Java, Indonesia: Impact of economic and institutional changes 总被引：2，自引：1，他引：1
J. W. Nibbering 《Agroforestry Systems》1999,46(1):65-82
This paper analyses how farmers in the Sewu Hills, a limestone hill complex in Java, were led to grow trees on their holdings.
In the past, the area had been notorious for its deforestation, soil erosion and poverty. A historical analysis of change
in land use in the area bears out a number of factors that were conducive to these changes: increased crop productivity, depletion
of forest resources, better marketing opportunities for tree products, greater security of the trees and increased non-agricultural
employment opportunities. Tree planting campaigns launched by the government provided the population with important incentives,
establishing a critical mass of farmers adopting tree growing. Trees and their products have diversified, buffered and expanded
household economies in the Sewu Hills. Yet it remains to be seen whether the system can withstand the economic and social
pressures the area is facing today. A historical, multi-level analysis of land use adds considerably to cross-sectional studies
in understanding what causes farmers to grow trees on their fields.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
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为探寻科尔沁沙地东南部草地生产力自然恢复的主要限制因素,该文采用3因素2水平析因设计研究了水、氮、磷添加对沙质草地的影响。8种处理分别为添加水(W)、加氮肥(N)、加磷肥(P)、加水+氮肥(WN)、加水+磷肥(WP)、加氮肥+磷肥(NP)、加水+氮肥+磷肥(WNP)和对照(CK),每种处理6次重复,随机分配在48个4m×4m的样方中,样方之间留2m缓冲带。研究结果表明:科尔沁沙质草地生产力的恢复受氮素的限制,与水和磷无关;2005年生长季所有添加氮肥的样方,生物量和地上净初级生产力均较对照明显增加(P<0.05);禾本科根量在地下生物量中占优势。受限于地下生物量测定,目前的研究可能低估了我国北方草地的净初级生产力。 相似文献
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林地资源配置及其驱动机制 总被引：1，自引：0，他引：1
林业可持续发展必然要求建立与之相适应的林地空间秩序,合理林地空间秩序是林地资源配置的具体表现,林地资源配置具有经营主体的自愿性、经营目标的明确性、配置方式的多样性以及林地空间秩序的可建设性等特征。合理林地空间秩序的建立、维持和调整与经营单位生产过程紧密相联,两者相互依赖、相互影响。林地资源配置归根结底是一个利益驱动过程,因此,驱动机制在林地资源配置中必然会起到重要作用。 相似文献
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广西海岸沙地木麻黄防护林带的生物量和生产力 总被引：1，自引：0，他引：1
对海岸沙地木麻黄防护林带生物量和生产力的研究结果表明:13年生木麻黄林带的生物量为100.01t.hm-2,生物量的大小序列为干材>根系>树枝>叶枝>干皮>枯枝。立木生物量总量的空间格局是随树高的增加而减少,不同器官生物量的空间分布却有所不同,干材和干皮生物量随树高的增加而减少,树枝生物量则主要集中在树冠中层或中下层,叶枝则主要分布在上层或中上层。沙地木麻黄林带具有较高的生产力,为7.693t.hm-2.a-1。海岸沙地木麻黄这种生物量和生产力水平足以说明它对海岸沙地的生态环境具有很强的适应能力。 相似文献
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Chuanqi Yan Weizhang Yang Chunte Li Xiaozong Han Fenglin Ma Wanyun He 《Agroforestry Systems》1989,8(1):83-90
The cutting down of forest and the extension of arable fields led to severe degradation of the land in the Mao Jia Shan valley. In restoring the environment and the agricultural productivity, the intricate ecological relations within and between the diverse types of land utilization are taken into account. Strategies are adopted to the ecological sub-systems, such as arable fields, grassland, orchards, sloping woodland, fish ponds, marshes etc.Within the first 3 years soil erosion was reduced to 1/50th of its previous value and agricultural productivity increased 2.3 fold. Balances of organic matter, N, P and K have been calculated and predicted upto the year 2000. The model, based on the evaluation of fuzzy sets of multiple factors, indicates a further large improvement in productivity and local rural economy. 相似文献
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文章从肃北县自然条件和林地资源现状出发,提出规划期内的林地保护利用目标、林地结构与布局、林地用途管制和林地保护分级管理。 相似文献