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81.
采用扫描电子显微镜-X射线能量散射分析(SEM—EDXA)法对柠檬桉Eucalyptus citriodora木材中晶体的轴向分布、径向分布、形态和含量以及硅石的纳米结构进行了分析。结果表明:①柠檬桉木材中晶体主要分布在木射线细胞,形态多为菱形晶体;②柠檬桉木材钙元素含量高的可达所有元素含量的22%以上;③柠檬桉木材中晶体的纳米尺寸在350~400nm,晶体尺寸大小从树基向树梢呈递减趋势。图4表1参9 相似文献
82.
以永宁—泸沽湖地区摩梭人自然圣境中的山林自然圣境为研究对象,运用生态学方法,首先对该区域植被类型进行初步判断,再选择相似海拔、土壤条件的同样植被类型的对照样地,与圣境样地进行详细的样方调查,从而在生态系统水平上,对传统文化在生物多样性保护的影响方面进行定量分析。说明在生态环境遭受破坏的情况下,由于传统信仰文化的原因而建立的山林自然圣境保留了较为完整的自然垂直带谱。调查和定量分析的结果表明,与相同植被类型对照样地相比较,圣境具有更高的生物多样性,在植物群落物种组成上更接近于原始林地。定量分析的结果还表明,圣境对植被的保护作用是显著的,这种保护作用沿山地垂直梯度有上升效应,海拔越高,这种保护作用越明显。从而提示人类高度重视圣境对较高海拔地段自然生态系统的维持和保护作用。 相似文献
83.
指出了停止天然林商业性采伐是党中央、国务院为保障森林资源安全,增强森林生态功能而做出的一项重大决策,对于推进生态文明建设有重大的意义。通过实地调查,认真分析了仙游县天然林停伐管护补助工作中存在的问题,并提出了切实可行的实施建议。以供参考。 相似文献
84.
东北林区森工企业虚拟经营模式的研究 总被引:3,自引:0,他引:3
根据国家振兴东北老工业基地和治理森工"两危"的要求,结合东北林区生产经营管理实际情况,应信息网络技术飞速发展和随之而来的经营变革,提出森工企业虚拟经营新理念,旨在破除思维定势,走出传统林业企业经营管理模式的路径依赖,实现理论创新,提出以顾客为中心、追求时间与速度的全新的林区现代虚拟企业运作模式,以适应网络时代对林业企业竞争模式的新要求。 相似文献
85.
Tropical forests worldwide are undergoing rapid changes due to increasing human populations and varied land use practices. In an effort to protect these forests and their species, the number of protected areas has increased exponentially in recent decades. Clearly protected areas play a crucial role in conservation efforts and this strategy has been found to be successful in several studies. However, protected areas are often embedded within a matrix of other land cover types, including non-protected forests, agricultural fields, or urban areas. It is therefore critical for park management to think beyond the borders of their protected areas and work to maintain ecological integrity of the surrounding matrix and the connectivity between protected areas. This study integrates remote sensing, GIS and field observations to examine the effects of different management strategies on land cover changes. As a case study we examine a tiger reserve in Central India which is surrounded by commercially managed forests, representative of many protected areas throughout India. Findings of this study show that while protected areas play an important role in conservation, alternative approaches including favorable management policies could also be effective to extend conservation over larger areas. 相似文献
86.
Understanding users’ spatial distribution in forest park is crucial for providing visitors with quality recreation experiences and for park planning and management. Utilizing users’ spatial distribution data, this study aims at investigating associations between trail use level and trail spatial attributes, through examining two large urban forest parks (Gongqing forest park and Paotaiwan forest park) in Shanghai, China. Users’ spatial distribution was measured utilizing GPS trackers with the interval of 10 seconds. This study conceptualizes trail spatial attributes as trail metric attributes and trail configurational attributes. Trail metric attributes include trail mean distance to gates, length, width and level of enclosure, which are calculated based on park map and on-site observation. We computed trail configurational attributes utilizing space syntax theory, which comprise measures of global integration, control, and connectivity. Trail connection with features/facilities, visual connection with water and shading are included as covariate variables. In total, we obtained 134 valid samples in Gongqing forest park and 210 valid samples in Paotaiwan forest park for analysis. Multivariate regression analyses indicate that when involving covariate variables, consistently in both parks, a greater trail usage is significantly related to trail shorter mean distance to park gate, trail width wider than 3 meters, higher global integration and higher control values. Collectively, these four trail spatial attributes explained 31.7 % (p < 0.001) and 27.3 % (p < 0.001) of the variances in trail use level in Gongqing forest park and Paotaiwan forest park. These findings provide direct implications to park designers and managers for providing visitors with different desirable social conditions, and ultimately improve users’ experiences and satisfactions. 相似文献
87.
目的 林内降雨的空间变异对林地土壤水分、林下植被生长有重要影响,准确刻画其空间变异特征,并确定其收集器的合理布设数量,有助于准确理解森林对水文的影响。 方法 于2021年6—10月,在六盘山半湿润区香水河小流域的华北落叶松(Larix gmelinii var. principis-rupprechtii (Mayr) Pilg.)纯林样地,利用样地内布设的40个林内降雨收集器收集每场降雨事件的林内降雨量,分析展叶和落叶期林内降雨的空间变异特征,并量化雨量收集器的合理布设数量。 结果 (1)整个生长季,林内总降雨量440.0 mm,占同期林外降雨量的77.5%,林内降雨空间变异系数28.23%;展叶和落叶期,林内总降雨量分别为153.8 和290.2 mm,占同期林外降雨量的73.0%和80.2%,林内降雨空间变异系数分别为36.0%和18.5%。总体上,林内降雨空间变异随次降雨量、雨强和降雨历时的增加先快速下降后逐渐趋于稳定。(2)整个生长季及展叶和落叶期林内降雨的块基比分别为0.042、0.012和0.275,变程分别为4.8、4.0和6.5 m。(3)在95%置信区间内,若将误差控制在5%内,至少需在展叶和落叶期分别布设17和14个截面积为235.58 cm2的雨量收集器。 结论 受降雨量和冠层结构差异影响,华北落叶松林内降雨空间变异在展叶和落叶期存在差异,不同时期雨量收集器合理布设数与林内降雨空间变异密切相关,要确保整个生长季林内降雨评估的准确性,应重视不同时期雨量收集合理布设数差异的影响。 相似文献
88.
89.
Uemeson José dos Santos Gustavo Pereira Duda Marise Conceição Marques José Romualdo de Sousa Lima Eduardo Soares de Souza 《Arid Land Research and Management》2019,33(3):255-273
Caatinga is a Brazilian dry ecosystem that occupies around 1 million km2 and is one of the largest tropical dry forests of the world. About 46% of the area that was originally covered has been deforested. Land use can cause pronounced reduction in soil carbon stocks that play a major role in the global carbon cycle. The objective of this study was to improve our understanding of the effect of land use on oxidizable carbon fractions, total carbon stocks and humic substances in different layers of soil in a Brazilian semi-arid region. We analyzed soils from tropical dry forest (TDF), forest succession with Anadenanthera falcata (ANA), with Tabebuia alba (TAB), secondary scrubby regeneration (SCR), and non-irrigated maize (MS). Forests showed larger fractions of more labile carbon, except for TDF. The most recalcitrant fraction of carbon stock, humin fraction stock, with the different land use decreased by 38–53% compared to TDF. Oxidizable carbon fractions, carbon stocks, and humic fraction stocks were able to differentiate the successional land uses and agricultural cover from TDF, mainly in the 0–5?cm layer. Our results show that changes in land use, especially with ANA forest succession, showed a larger labile carbon fraction, indicating easy decomposition and loss. Our results provide an alternative tool for the management of deforested areas in tropical dry caatinga ecosystems. This would contribute to the conservation of dry forest systems and could serve as guideline for sustainable management of agriculturally impacted caatinga areas. 相似文献
90.