首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 125 毫秒
1.
蕉林     
绿了,芭蕉黄了,香蕉红了,美人蕉好一个蕉林的世界好一个蕉林的夏天绿了,芭蕉黄了,香蕉红了,美人蕉好一个蕉林的世界好一个蕉林的夏天绿了,芭蕉黄了,香蕉红了,美人蕉好一个蕉林的世界好一个蕉林的夏天绿了,芭蕉黄了,香蕉红了,美人蕉好一个蕉林的世界好一个蕉林的夏天绿了,芭蕉黄了,香蕉红了,美人蕉好一个蕉林的世界好一个蕉林的夏天绿了,芭蕉黄了,香蕉红了,美人蕉好一个蕉林的世界好一个蕉林的夏天蕉林@朱建武~~  相似文献   

2.
同志们 :这次直属院森林资源监测工作座谈会是经局领导同意召开的 ,充分体现了国家林业局对直属院工作和森林资源监测工作的重视和关心。经过一天半的讨论 ,大家献计献策 ,共商发展大计 ,会议取得了显著的成效 ,达到了预期效果。这次会议一是交流了情况 ,总结了经验 ,起到了相互学习、相互借鉴的作用 ;二是统一了思想 ,明确了主题 ,进一步坚定了做好森林资源监测工作的信心 ;三是理清了问题 ,研究了对策 ,探讨了森林资源监测工作的发展思路 ;四是讨论了各项核 (调 )查以及连清汇总方案 ,修改了办法 ,完善了核 (调 )查的内容。尤其是计资司、…  相似文献   

3.
通过清洁生产工作,提高了企业及员工对清洁生产审核的认识,审核了研究对象有关单元操作、原材料、产品、用水、能源和废物的资料。确定了废弃物的来源、数量及类型,并根据审核结果制定了废弃物消减的目标,制定了经济有效的废物控制对策。从而提高了企业管理水平,提高了原材料、水、能源的使用效率,降低了成本,减少了污染物的产生及排放量。提高了员工素质,促进了企业技术进步,为企业带来一定的经济、环境和社会效益,为其他企业提供了范例。  相似文献   

4.
常用树种抗污染特性的浅析   总被引:5,自引:0,他引:5  
<正>人类在改造环境征服自然的历史进程中,特别自20世纪初以来,以空前的工业发展速度,建立了现代的物质文明。但同时,也由于人类活动引起了自然条件的变化。人们的物质条件提高了,但环境条件却变糟了:天变灰了,地变热了,绿地少了,硬地多了,可用水少了,污染水  相似文献   

5.
为期一天的斤直属单位组织人事工作座谈会,现在就要结束了。会上,斤直属单位就近年来的组织人事工作作了汇报,智华同志对人事教育处两年来的工作进行了总结回顾,分析了存在的问题,提出了今后工作的建议和打算,我完全同意。这次会议时间虽短,内容丰富,总结了工作,交流了经验,提出了建议,畅谈了设想,达到了预期的目的。下面,我讲三个问题:  相似文献   

6.
对枫香次生林改造进行了为期4 a的研究结果表明:枫香次生林改造改善了林木生长的环境,有效利用了林地,促进了林木的生长,提高了林分的价值,获得了良好的经济效益。  相似文献   

7.
通过对人工针阔混交林的培育试验,结果表明:培育人工针阔混交林改变了生态环境,调整了林种结构,涵养了水源,提高了林地的营养含量,调节了气候,保护了物种多样性,充分展现了混交林功能效益和潜在的性能。  相似文献   

8.
指出了近年来生物质锅炉在我国部分行业中得到了应用,并取得了不错的效果:节约了大量能源、保护了自然环境.介绍了生物质锅炉的含义及其生产排污情况,分析了对其推广和使用的意义,对生物质锅炉使用过程中存在的问题及未来发展趋势进行了深入探讨.  相似文献   

9.
指出了在很长的一段时间内,我国以破坏生态环境做为代价,虽然促进了我国经济的快速发展。但是导致了我国的环境受到了严重的污染。从大气污染治理形势及问题进行了详细探讨,分析了在治理大气污染时存在的问题,根据原因,提出了科学合理的解决方案。  相似文献   

10.
今年以来,合浦县林业局根据区、市、县关于整顿机关作风的指示,有的放矢地全面整顿机关作风,收到了“五少五多”的良好效果。一是上班迟到早退的人少了,严守纪律的人多了;二是工作推波扯皮的人少了,办事讲效率的人多了;三是私事用公车的人少了,公事不用车的人多了;四是议论人和事的杂音少了,思想行动统一多了;五是公务开支少了,遵守廉政建设制度多了。合浦林业局整顿机关作风见效快@石帷宏  相似文献   

11.
Senbeta  Feyera  Teketay  Demel  Näslund  Bert-Åke 《New Forests》2002,24(2):131-145
Regeneration of native woody species was studied in the plantations and the adjacent natural forest at Munessa-Shashemene Forest Project Area, Ethiopia. The aim of the study was to test the hypothesis that tree plantations foster regeneration of native woody species. A total of 60 plots, having 10 × 10 m area each, were studied in monoculture plantations of 4 exotic species (Cupressus lusitanica, Eucalyptus globulus, E. saligna, Pinus patula) and an adjacent natural forest. Ages of the plantations ranged between 9 and 28 years. Soil seed bank analysis was also undertaken from soil samples collected in each of the 60 plots to examine the similarity between the soil seed flora and aboveground vegetation. A total of 56 naturally regenerated woody species were recorded beneath all plantation stands with densities ranging between 2300 and 18650 individuals / ha in different stands. There was a significant difference among plantation stands with regard to understorey density (standard deviation: 4836 ± 1341). Vegetation diversity was assessed through analyses of floristic composition, species richness and abundance. Generally, seedling populations were the most abundant components of the regeneration in most of the plantation stands, forming 68 % of the total regeneration count in all stands. A total of 77 plant species represented by 44 herbs, 13 woody species, 8 grasses and 12 unidentified species were recorded in the soil seed bank from all stands. Similarity between the soil seed bank and aboveground flora was very low implying that the role of soil seed banks is negligible rather dispersal plays an important role in the process of regeneration. These results support the concept that forest plantations can foster the regeneration of native woody species, thereby increasing biological diversity, provided that there are seed sources in the vicinity of the plantations.  相似文献   

12.
在延安对刺槐、油松、侧柏纯林及刺槐 侧柏、刺槐 油松混交林等几种黄土高原主要人工林群落外貌结构、林下植物多样性特征进行了研究.结果表明:混交林群落外貌结构较为复杂,林下植物群落类型各不相同;林下植物的Simpson多样性指数和Shnnon-wiener多样性指数分别为0.902 57~0.674 88和2.012 88~1.479 67,刺槐 油松林最高,16年生刺槐纯林最低;32年生刺槐纯林林下植物优势度最高者是糙隐子草,16年生刺槐纯林则为牡蒿,其它林型都是铁杆蒿;本地区选择防护林类型时,应优先选择刺槐 油松或刺槐 侧柏混交,对已有的成熟或衰退刺槐纯林可采取择伐萌蘖抚育,并间植油松或刺柏,形成针阔混交林.  相似文献   

13.
野生动物所有权是所有权的一种,它与其他所有权的区别在于客体的不同。文章阐述了野生动物的内涵,分析了野生动物的分类和野生动物与野生动物资源的区别。在明确野生动物含义的基础上,提出了野生动物所有权的概念,深入论述了野生动物所有权与野生动物资源所有权的差异和联系,并对野生动物所有权的主体、客体、内容进行了分析。  相似文献   

14.
Growing Acacia albida as a permanent tree crop, on farmlands with cereals, vegetables and coffee underneath or in between, is an indigenous agroforestry system in the Hararghe highlands of Eastern Ethiopia. However, there is practically no systematic record or data on the merits and benefits of this practice.The paper presents the results of an investigation into the effects of the presence of A. albida on farmlands on the yield of maize (Zea mays L.) and sorghum (Sorghum bicolor L. Moench). Twenty seven plot pairs each consisting of one plot underneath the A. albida foliage cover and the other in the open, away from the tree-on farmers' fields, in a 40 km radius around the Alemaya College of Agriculture, were sampled and the yield components analyzed. A statistically significant increase in crops yields by 56% on average was found for the crops under the tree canopies compared to those away from the trees. This increase was caused by the improvement in 1000 grain weight and number of grains of plants under the tree, indicating that the trees enhanced the fertility status of the soil and improved its physical conditions in terms of crop growth.Additional benefits from the A. albida trees include supply of fuelwood and fodder. Quantitative estimates of these outputs as well as their monetary values are presented in the paper. However, in order to realize these benefits to a discernible extent, higher stand densities of the tree than at present are required.Based on an enquiry about the farmers attitude towards A. albida, the prospects for an extension of this promising agroforestry technique are discussed against the background of the state and trends of development of agriculture in the area. It is surmised that despite some shortcomings like the relatively slow and highly variable growth of A. albida and a conflict with the spreading cultivation of Ch'at (Catha edulis Forsk.), the prospects of extension of this technique are good. It is recommended that its propagation should be incorporated into the programmes of the extension agencies of the various governmental agencies concerned with land use.  相似文献   

15.
油茶病虫害发生的现状及其环境因子研究   总被引:1,自引:0,他引:1  
对国内油茶病虫害发生相关研究进行了总结,分析了我国油茶病虫害的发生现状;结合油茶的地理分布、生态学特性和油茶病虫害的发生种类,提出与油条病虫害发生相关的环境因子.通过掌握环境因子的变化提高预测、防治油茶病虫害发生的频率,从而提高油茶的产量.  相似文献   

16.
The dynamics of K, Ca, and Mg were investigated during the decomposition of 14 litter types over a 3-year period on the upper and lower parts of a forest slope in a cool temperate forest in Japan. Potassium dynamics were divided into initial leaching phase and late phase. Initial K concentrations for the initial phase were correlated with the rate of decrease in K concentration during the initial phase. The late phase was characterized by seasonal fluctuations in concentration: K concentration increased from April to November and decreased during the winter period. The pattern of change in Ca concentration was divided into initial increase phase and late decrease phase in some litter types, or consisted of the late phase only in other litters. Calcium concentration of the initial litter was not predictable for the pattern of change in Ca concentration nor the rate of change in Ca concentration during the initial phase. Initial Ca concentration for the late phase was correlated with the rate of change in Ca concentration during the late phase. The pattern of change in Mg concentration was divided into initial leaching phase and late immobilization phase. Initial Mg concentration for the initial phase was correlated with the rate of change in Mg concentration during the initial phase. At the lower site, initial Mg concentration for the late phase was correlated with the rate of change in Mg concentration during the late phase, while such a relationship was not observed at the upper site. Concentrations of K, Ca, and Mg showed a convergent trend at the end of the study period. The final concentration differed between the upper and lower sites.  相似文献   

17.
采集农田、林地和盐碱地不同类型的土壤样本,采用偏最小二乘法结合OSC方法建立土壤有机质反演模型,运用交叉验证和外部验证相结合的评价方法进行比较分析。结果显示:采用平滑+MSC+OSC方法对光谱进行预处理,可以提高预测模型的精度。OSC因子个数和PLS主因子个数分别为6和4时,交叉验证决定系数R2为0.990 1,均方根误差为0.297 5,外部验证决定系数R2为0.926 1,均方根误差为0.283 6,模型达到最优。表明对光谱进行OSC预处理后建模是可行的,OSC降低与浓度阵无关的光谱信号,并且减少建立模型的主因子个数,进一步提高模型的精度和稳定性。  相似文献   

18.
Martínez Pastur  G.  Arena  M.  Curvetto  N.  Zappacosta  D.  Eliasco  E. 《New Forests》2003,26(3):201-215
In vitro rooting constitutes a difficult step during the micropropagation process of forest species. The successive media culture technique represents one way to overcome this barrier and includes modifying physical (e.g. photoperiod) and chemical (e.g. flavonoids) factors during the rooting phases. The aim of this study was to obtain a successive media protocol based on the incorporation of flavonoids during the in vitro rooting of Nothofagus nervosa. The factors evaluated were the type, concentration, and combination of flavonoids in relation to the rooting phases, the presence of IBA in the culture medium, the photoperiod, and the effect of flavonoids on total tissue peroxidase activity. The photoperiod used included a darkness period during the rooting induction stage and the presence of 0.61 µMIBA in the culture medium. The results showed that flavonoid incorporation at a concentration of 20 µM accelerated the appearance of roots and improved the quality of the already formed ones. Each type and concentration of flavonoid produced different responses, with (±)naringenin giving the best results. The latter caused a peak in the peroxidase activity that was absent in the control treatments. This work allowed identifying an optimized rooting protocol through a successive media culture technique that improved the speed of appearance, as well as the quantity and quality of roots for a single N. nervosa clone.  相似文献   

19.
Dehesas are an agrosilvopastoral system that has enhanced the maintenance of an extraordinarily high biodiversity. The traditional use is characterized by mixed livestock raising at low stocking densities, employment of hardy regional breeds and an elaborated maintenance and exploitation of holm oaks. Livestock production has traditionally been accompanied by arable systems with long rotations and closed nutrient cycles without external inputs of fodder, fertilizers and agro-chemicals. Modern trends are a specialization toward lamb and beef production and the employment of intensive techniques like free-range grazing at high stocking levels or crossbreeding with high-performance breeds. A model income statement shows that livestock create an income of 49.91 US$ per ewe per year on an average basis. The central problem for the continuity of the dehesas is the gradual decay of the tree canopy. Intensification of agricultural production and the abandonment of traditional grazing practices additionally threaten biodiversity within the dehesas. The authors suggest the foundation of a biosphere reserve in Cuatro Lugares as a framework for a sustainable development of the dehesas.This revised version was published online in November 2005 with corrections to the Cover Date.  相似文献   

20.
本文对木材热值的测定方法进行了研究。为了提高试验的精确度,改进了试样的容器;减少试样辅助添加剂引入的误差;考虑了含脂材挥发物对热值的影响,提出了一个实际通用的测试方法。通过对二十四种样木的测试,综合分析了测试误差、生态差异以及营林因子等的影响,对薪材热值的树种间差异和生态因子对热值变异时影响进行了研究。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号