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随着对古树名木保护意识的提高,对古树名木的认识也应更加深入.北京的古树名木数量位列榜首,其自然属性和文化属性均具有显著特征,共同构成了环境艺术中风景构成、人格象征和人化自然3个层次.通过对北京古树名木意象生成基本结构、生成机制和美感体现以及审美价值评价进行解读,以期为更好地维系北京古树名木生命奠定基础. 相似文献
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古树是珍贵的林木资源,也是宝贵的文化遗产。文章以北京颐和园为例,通过运用支架、修剪、树体修复等古树树体保护技术,可提高古树养护水平,改善古树生存状态。 相似文献
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针对北京石刻艺术博物馆的2株古银杏树近年来出现衰弱现象,为更好地保护古树,对2株古银杏树采取了复壮措施,并加强针对古树的科学保护,以巩固复壮成果。 相似文献
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近日,由首都绿化办和北京市总工会共同主办的"认养一棵古树,保护一片绿色,传承一段历史"——2013年古树名木认养推进活动现场会在北京朝阳区日坛公园举行。本次活动旨在宣传认养企业、家庭、个人强烈的环境意识和高度的社会责任感,号召社会各界人士关注首都古树名木保护工作,引领社 相似文献
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古树名木保存了弥足珍贵的物种资源,加强古树名木和古树后续资源的保护,对于推进生态文明和美丽中国建设具有十分重要的意义。本文基于广东省古树名木普查的数据,在收集资料的基础上,从珠海市古树名木数量、树龄状况、树种组成、位置分布及生长情况等方面分析了珠海市古树名木资源现状,总结珠海市古树名木保护工作的现状和存在的问题,并提出相应的保护对策,为珠海市古树名木资源的可持续保护提供参考。 相似文献
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古树名木是具有自然与人文双重意义的珍贵自然资源,有着重要的科学与人文价值。本文利用访问座谈、查阅资料与实地调查的方法,对五鹿山国家级自然保护区境内的古树名木进行了全面普查与研究,对保护区内古树名木的种类数量、保护等级与地域分布进行了总结。通过排查,发现了古树名木保护工作中存在的一些问题,并提出了针对性的对策与建议。本文通过挖掘整理古树名木资源,提出科学管护举措,有助于进一步挖掘古树名木在生态、科研、人文、地理、旅游诸方面的价值,促进保护区对古树名木管护工作的完善。 相似文献
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以原有的桂林市古树名木的调查资料为依据,对桂林市的古树名木进行了更广泛的调查;对以往记录的古树名木进行复核、跟踪调查,并针对该古树名木的现状及存在问题提出相应的管理和保护措施。 相似文献
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对北京大学校园内银杏树分布及喜鹊营巢情况进行了调查。调查表明:北京大学银杏树的喜鹊营巢率明显低于落叶乔木的喜鹊平均营巢率。建议绿化部门在种植银杏树时,把喜鹊的营巢喜好考虑在内,注意保护校园里的古银杏树,而且配置时应以混植、对植为主。 相似文献
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Urban trees play an important role in green infrastructure planning for the ecosystem services they provide. These services include carbon sequestration, the provision of clean air through oxygen production and filtering of airborne pollutants, and the offsetting of the urban heat island effect by providing shade and cooling. In addition to the well-studied positive effects of urban trees, under specific conditions, there are some unwanted side effects that need to be considered. Such negative side effects, such as allergies caused by tree pollen, traffic hazards from falling trees or tree parts or damage from roots or branches in resource supply or waste disposal infrastructures, are termed ecosystem disservices. An ecosystem disservice that is not very often illuminated in the urban context is the presence of poisonous urban trees. This paper provides a spatially explicit view of the distribution of poisonous urban trees in the city of Berlin, relating the spatial distribution of the hazard from this urban ecosystem disservice with the conditions under which it can have the most damaging effect by considering nearby playgrounds and areas with a high population density of children under 5 years old, the most vulnerable group within the urban population. 相似文献
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Increasing human populations and rapid urbanization in sub-Saharan Africa have prompted the development and maintenance of urban green infrastructure, including urban trees for sustainability, human wellbeing, liveability and climate resilience. However, there are still insufficient amounts and large inequities in the distribution of trees between and within towns and cities of the Global North and South. In South Africa, urban green space planning and planting are encoded in several policies at national level. However, these policies are rarely translated into specific guides, standards or actions, and consequently disparities in urban trees and green space distribution persist. This study assessed the prevalence of urban trees in domestic gardens in low-cost housing areas (LCHAs) of eight small to medium-sized towns in the Eastern Cape province of South Africa and examined residents’ perceptions in this regard. This was done via surveys with 800 households in old and recently developed LCHAs. The results revealed that most households (52 %) had at least one tree in their yard, with more households in the older neighbourhoods (60 %) reporting having trees than in the newer ones (44 %). Most of the trees (66 %) had been deliberately planted as opposed to natural regeneration. Experience of formal urban tree planting programs was low, but 75 % of residents expressed willingness to participate in the future, preferably in tree planting and maintenance. Urban green spaces and trees cannot be an afterthought in the development of sustainable human settlements, and municipal plans should reflect tangible commitments in this regard. Meeting goals for greener LCHAs requires the involvement of local residents, and for municipal authorities to be receptive to the wishes of residents and willingness to green their residential areas. 相似文献
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The influence of trees in urban areas is typically assessed using urban microclimate models. These models rely on wind tunnel experiments using small-scale tree models to verify and validate their predictions of the flow field. However, it is not known sufficiently to which extent small model trees used in wind tunnel studies can recreate the behavior of large trees found in cities. In the present study, the drag coefficient and the turbulent flow downstream of model trees are compared with the ones of natural trees of a similar size to determine whether both types of tree provide similar aerodynamic characteristics. Therefore, measurements of the drag force and the flow field, using particle image velocimetry, are performed. The aerodynamic characteristics of the small trees are compared with the ones measured on larger mature trees from previous studies. The present study shows that the drag coefficients of model and natural trees are similar only if both types have a similar aerodynamic porosity and if the model tree can undergo an aerodynamic reconfiguration similar to that of a natural tree. Such reconfiguration implies the reorientation of the branches and leaves due to wind. A study on the influence of seasonal foliar density variation shows that the foliage configuration plays a critical role on the drag coefficient and the flow field. A defoliated tree, such as a deciduous tree in winter, is shown to have a substantially lower drag coefficient and a negligible influence on the flow. 相似文献
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In order to study decay, and to improve the management and protection of old urban trees, a total of 256 felled urban trees were examined during 2001–2003: 95 Tilia spp., 74 Betula spp., and 87 Acer spp. Most of the trees (73%) were located in the main parks and along the main streets in the downtown area of Helsinki City, Finland. The mean age of the trees was over 60 years, and the majority (64%) were old park trees. Poor condition and increasing risk of failure were the main reasons for felling in 82% of the cases. Thirty three percent of these trees were degenerated or dead, but the amenity value of 14% of the risk trees was still high. The latter were old, big trees which posed a potential hazard, but had a vital and balanced crown.Some characteristic profiles for potential failure were identified for each of the tree species studied: Ganoderma lipsiense in the butts and hollows in the stems of Tilia spp., weak fork formations together with Rigidoporus populinus on Acer spp., and degeneration together with decay in the stem on Betula spp.Decay fungi most commonly identified were R. populinus, G. lipsiense, Inonotus obliquus and Piptoporus betulinus. In addition, Kretzschmaria deusta was very common in three of the parks, and on every one of the tree species investigated. 相似文献
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Many authors claim that trees planted along streets are weaker because of environmental pollution, especially high soil salinity, which results in greater susceptibility to attacks by pathogens. The Tilia ‘Euchlora’ (Crimean linden) is described as one of the urban greenery species that is most prone to the effects of salinity. The aim of this research was to assess the influence of salt stress on the lime aphid abundance on the leaves of Tilia ‘Euchlora’. The average number of aphids was lower for trees growing along the street and subjected to de-icing salt than in the controlled park area. It was strongly negatively correlated with the Na and Cl level in the leaves, whereas it was positively correlated with the content of N and P. The study showed that the aphids’ abundance was most strongly influenced by the N and Cl content in the leaves (although in opposite ways). When the amount of nitrogen increased by 1.0% (from 2.0 to 3.0%), the abundance of aphids increased by 116%. An increase by 1.0% (from 1.0 to 2.0%) in the Cl content in the leaves resulted in a decrease in the abundance of aphids by 36%. The toxic Cl level (over 1%) was exceeded only in the leaves of trees growing along a busy street (79% of the examined individuals in this location), whereas it ranged from 0.23% to 0.40% for the trees from the park. There was concluded that aphids probably prefer trees with healthier leaves for their feeding, i.e. leaves of lower amount of Cl and Na, while with higher concentration of N. 相似文献
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Mature trees provide a range of ecosystem services in urban landscapes, represent important wildlife habitat, and impact positively on human wellbeing. However, mature trees are perceived as a risk to people and infrastructure and occupy land suitable for development. Trees are slow to reach ecological maturity and thus difficult to replace when removed. In this study, we: (a) quantified native canopy cover retained during residential development using aerial imagery; (b) identified where native trees are/are not retained within residential developments with a focus on mature trees; and (c) evaluated the effectiveness of current legal mechanisms for protecting native trees during residential development. Native canopy cover was reduced by 49% during residential development. Mature trees had the highest probability of retention within residential developments if they occurred within intact remnant vegetation. A lower probability of retention for mature trees was observed in urban green space, and almost no mature trees were retained in other areas within residential developments, such as residential blocks and road verges. Mature trees had greater probability of retention where the jurisdiction offered some legislative protection. The loss of mature trees during residential development could be reduced with a greater focus on avoiding the removal of existing trees during the planning stage rather than offsetting the impacts elsewhere; and by designing green space within residential developments to ensure adequate separation between mature trees and people and infrastructure. 相似文献