共查询到20条相似文献,搜索用时 609 毫秒
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木棉(Gossampinus malabarica)又名攀枝花、红棉、英雄树、烽火树,属木棉科木棉属落叶高大乔木.木棉广泛分布在我国四川、云南、贵州、广西、广东,生长在江河沿岸、山地阳坡及村边道路旁,喜光、耐高温,对土壤要求不苛刻.在四川攀枝花地区木棉树于1月-2月份开花,先花后叶,花色艳丽,有红色、金黄、淡黄色等颜色,树形高大伟岸,是优良的园林绿化树种.木棉树现是攀枝花市市花和广州市市树,在园林绿化中常作行道树、庭荫树、景园树、盆景树等.木棉经嫁接后2 a-3 a开花,嫁接苗可作盆景矮化栽培,观赏价值高.本文介绍了木棉的嫁接育苗技术. 相似文献
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One compound approach combining factor-analytic model with AMMI and GGE biplot to improve multi-environment trials analysis 总被引:1,自引:0,他引:1
To improve multi-environmental trial(MET)analysis,a compound method—which combines factor analytic(FA)model with additive main effect and multiplicative interaction(AMMI)and genotype main effect plus genotype-by-environment interaction(GGE)biplot—was conducted in this study.The diameter at breast height of 36 open-pollinated(OP)families of Pinus taeda at six sites in South China was used as a raw dataset.The best linear unbiased prediction(BLUP)data of all individual trees in each site was obtained by fitting the spatial effects with the FA method from raw data.The raw data and BLUP data were analyzed and compared by using the AMMI and GGE biplot.BLUP results showed that the six sites were heterogeneous and spatial variation could be effectively fitted by spatial analysis with the FA method.AMMI analysis identified that two datasets had highly significant effects on the site,family,and their interactions,while BLUP data had a smaller residual error,but higher variation explaining ability and more credible stability than raw data.GGE biplot results revealed that raw data and BLUP data had different results in mega-environment delineation,test-environment evaluation,and genotype evaluation.In addition,BLUP data results were more reasonable due to the stronger analytical ability of the first two principal components.Our study suggests that the compound method combing the FA method with the AMMI and GGE biplot could improve the analysis result of MET data in Pinus teada as it was more reliable than direct AMMI and GGE biplot analysis on raw data. 相似文献
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Natural spruce-fir mixed stand is one of the main forest types in the world,and also has huge ecological,economic and social benefits.According to the structural characteristics and succession laws of natural spruce-fir forest,it is urgent and significant to develop scientific management measures for natural spruce-fir mixed stand in line with local conditions.The article outlined the characteristics of the distribution and structure, regeneration and succession laws of natural spruce-fir forest,and analyzed the current situation and existing problems of natural spruce-fir forest management.The following recommendations were eventually made:1) In no cutting area,all logging activities should be banned.In a restricted cutting area,the cutting intensity should be generally controlled within 15%of the stock volume before cutting.On the commodity forest management area, the appropriate cutting intensity should be determined according to the volume per hectare,determine and classification management should be implemented in accordance with the characteristics of forest,to ensure the scientific selective cutting.2) Closure for afforestation,planting and repair planting should be adopted on vegetation-intensive land,sparse shrubs covered land and harvesting slash,in order to accelerate natural regeneration.3) The in situ conservation should be conducted in nature reserves and scientific experiment stations of rare and endangered species,such as Abies chensiensis,Picea neoveitchii,Abies vuanbaoshanensis,to reduce human destruction.4) It is supposed to collect seeds in time,establish nursery,actively establish forest, expand artificial population and promote natural regeneration. 相似文献
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《技术与市场》2007,(1):23
当前现代化的航天、航空、汽车、机械、电子、民用建筑、化工等行业迫切要求具备很高的力学性能及耐热、耐磨、耐化学性能的材料.因此高分子材料发展的一个重要方向就是通过对现有聚合物进行物理和化学改性,使其进一步高性能化、结构化、工程化.北京化工大学研制的聚氯乙烯合金是通过挤出机的力学、化学作用及接枝、复合技术使聚氯乙烯塑料工程化,成为物理性能可与ABS相比拟的新材料.聚氯乙烯合金具有高流动性、高韧性,完全可以代替ABS注塑计算机、电视机、冰箱、照相机、仪表等外壳.聚氯乙烯合金还具有良好的耐寒性,可制作各种规格的异型材,包括门窗、上水管道等.产品市场前景好,具有很强的竞争力,有很好的经济效益和社会效益. 相似文献
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This paper proposes an automatic method of pore combination recognition,which is an important feature to hardwood recognition.After extracting edge from wood microscopic cross-section, based on area histogram of the similar circle regions,the method classifies all regions into two classes with maximum between-class variance,so as to distinguish the pore from other textures,which are similar in shapes but different in sizes.Meanwhile, second objective function about average area of closed regions is used to improve the pore segmentation performance.At last,the method uses adjacency degree of pore set to judge pore combination.The experiments demonstrate that the task of pore segmentation can be completed successfully for all kinds of pore distribution and combination,and also the correct combinations of pores are given. 相似文献
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According to the unification principle of system structure and system function of the Water Resource Conservation Forests,seven factors were selected from stand spatial structure,trees structure and healthy of woods,the multifunction management optimization model target was confirmed by using nonlinearity multi-objective programming approach, and the target function-stand spatial structure homogeneity index was defined to establish spatial optimization models with restraining conditions set up in diversity of stand structure and spatial structure.The spatial structure of available typical stand in the wet land area in southern Donting Lake was optimized by means of selective cutting and reinforcement planting.The results showed that the spatial structure was improved obviously and trees diversity and stand health were not weakened.It’s suggested that the established optimization model can effectively guide multifunction management,stand structure optimization and the steadiness of ecological ecosystem and it is convenient and operable in practice,and it’s very important to protect and recover ecosystem of Water Resource Conservation Forests. 相似文献
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森林害虫测报的电脑网络通信 总被引:2,自引:0,他引:2
通过研究实现了福建省森防站与福建省南平地区森防站、三明市森防站之间的异地远程森林害虫测报电脑网络的通信。达到自动化传递森林害虫测报信息的目的,替代了传统的缓慢信函传递形式。 相似文献
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林分断面积组合预测模型权重确定的比较 总被引:2,自引:0,他引:2
引入组合预测方法以提高林分断面积预测的精度及2类模型(林分水平模型和单木水平模型)预测林分断面积的兼容性。组合预测法能够充分利用各单个模型的有效信息,从而提高预测精度,而单个模型权重的选取对提高组合预测法的精度至关重要。本研究基于北京山区油松连续清查数据,利用误差平方和法、方差协方差法和最优加权法确定林分断面积组合预测模型的权重。结果表明:组合预测法能够提高预测精度,同时利用最优加权法所建立的林分断面积组合预测模型其预测精度最高,方差协方差法次之,误差平方和法预测精度最低。 相似文献
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介绍了信息量模型以及信息量模型与GIS的结合,描述了建立森林病虫害空间预测信息量模型的4个步骤:因子的选取、信息量模型的建立及公式计算、信息量结果值的分级、综合信息量图的生成。讨论了基于GIS的信息量模型在森林病虫害空间预测中存在的问题和发展前景。 相似文献
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华山松主要病虫害综合治理研究 总被引:8,自引:0,他引:8
为了解决林业生产中华山松主要病虫害(华山松疱锈病、华山松腐烂病、华山松木蠹象、华山松球蚜)综合治理的技术难题,首次提出了华山松主 虫害综合治理技术。该技术以华山松为保护对象,以4种主要病虫害为治理对象,做好预测预报,采取以预防为主,营林技术措施为基础,生物防治为主导,在阈值原理调控下,科学地采取生物、物理、化不防治等治理措施,逐渐增加华山松森林生态系统的生物多样性,使其结构逐渐趋向合理,最终达到华山松主要病虫害的可持续控制和华山松森林生态系统的持续平衡发展,为华山松生产谋取最大的效益。 相似文献
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四川万岭菁楠竹林枯枝(死)状况与原因的研究 总被引:2,自引:0,他引:2
四川省万岭菁楠竹林枯枝(死)状况是严重的。1987~1990年系统研究表明,楠竹林老年竹枯枝(死)主要是由经营因素导致的,占63.87%。虫害和病害是壮年竹株枯枝(死)的主要原因,占15.64%。 为了进一步验证楠竹林枯枝(死)的主要综合因子,采用多元回归和数量化理论(Ⅰ)方法,通过电子计算机运算。建立了多元回归予测方程和数量化理论(Ⅰ)予测模型,供生产应用。 相似文献
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云南油橄榄病虫害调查与综合治理研究 总被引:1,自引:0,他引:1
对云南省油橄榄病虫害进行调查和研究,概述了油橄榄病虫害的种类及危害情况,提出了油橄榄抗病虫品种、预测预防措施及主要病虫害症状和综合治理措施. 相似文献
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近年来,我国森林病虫害的发生面积逐年递增,危险性病虫害不断出现.为了保护森林资源,防患于未然,必须及时开展森林病虫害监测与预测工作.以遥感图像为主要数据源,地理信息系统软件SuperMap Objects为二次开发平台,采用面向对象的方法和组件式GIS技术,结合病虫害监测与预测模型,以VB为开发工具进行二次开发,建立了林业病虫害遥感监测与预测系统,并以塞罕坝机械林场遥感数据为例,对本系统进行了测试.结果认为,系统技术先进、具有创新性,具有良好的界面和可操作性,结构合理,信息内容全面. 相似文献