大连市的行道树调查及应用

对目前大连市城市行道树的性状及应用现状进行调查分析,探讨行道树选择的原则,研究分析大连市城市行道树的发展前景与对策,并推荐适宜的大连市行道树种。     

城市行道树应用研究

分析了当前城市选择行道树原则,随后立足于九江应用行道树基本情况背景下,提出优化城市行道树的相关策略。     

北方常见行道树优、缺点及栽培养护要点(上)

<正>行道树选择的正确与否,关系到城市绿化建设的成败,已引起园林工作者的高度重视。本文将系统地分析北方常见行道树的优缺点,阐述行道树的栽培要点,为北方城市行道树的选择和应用提供借鉴,避免行道树选择上的盲目性。     

城市绿化行道树种选择要点

随着我国城市化进程的不断深化,城市绿化植物作为一种自然资源,在人们的生产生活中发挥着越来越重要的作用,起到了生态保护的功效。在城市结构中,道路是城市的经脉系统,而行道树又是城市道路建设的一项重要组成部分,所以,行道绿化树种的选择是否科学,会给城市生态环境带来极大的影响,本文介绍了行道树的概念,论述了对城市行道树种进行科学选择的意义,并归纳了绿化行道树种选择的基本要求和相关要点,以期为我国的城市绿化建设提供一定的理论参考价值。     

南郑县城市行道树的调查分析

行道树的选择应用,在完善道路服务体系、提高道路服务质量方面,有着积极、主动的环境生态作用。随着南郑县城镇一体化规划的形成,城市绿地系统规划再一次修编、调整,城市重点项目相继建设,南郑县县城骨架拉大,近几年园林绿化建设快速发展,城市行道树的景观效益、生态效益越来越受到人们的关注。本文从南郑县行道树的概念及作用、行道树的种类、行道树的选择应用以及对当地行道树的生长现状和统计调查进行论述,提出南郑县目前道路绿化亟待重视解决的问题。进一步丰富道路绿化景观,改善城市生态环境,打造山水南郑、诗画家园的绿色项链。     

南阳市行道树的选择

在对南阳市城市行道树的树种及种植情况进行调查的基础上,探讨了南阳市行道树树种选择早期、中期和现状的优缺点。     

驻马店城区行道树种调查及应用探讨

针对目前行道树绿化中存在的一些问题,从原因剖析入手,立足于现实,通过调查研究香樟、银杏、桂花、雪松等行道树种,分析驻马店城区的行道树应用现状。主要阐明城市行道树选择的原则,提出了改变当前现状,丰富城市行道树种的对策和建议。     

果树行道树应用问题分析及行道树选择探讨

果树是向人们提供美味果品的传统的园艺植物。随着我国经济的发展,人们对居住生活环境的要求的提高,观赏果树作为行道树的使用,可能是彰显城市形象,或是街为其名。本文从果树行道树的现状,及果树作为城市行道树应用存在的问题出发。阐述行道树的概念及生境条件,提出行道树的选择建议,以期实现行道树的应用在景观效果、实际条件和环保实用等多方面和谐发展,为今后城市行道树的选择提供参考意见。     

天津蓟县城区行道树资源调查

通过对蓟县城区的行道树进行调查,发现蓟县城区目前应用的行道树存在物种单调、更新不力等问题,必须依据生态学原理,做好树种筛选、城市规划与设计等方面工作。论述城区行道树选择的原则,在分析蓟县城区行道树应用现状的基础上,提出丰富城市行道树种的对策和建议。     

邳州市行道树绿化现状及发展对策

行道树是城市道路的绿色框架,也是城市道路景观的一个重要组成部分。它对于改善区域生态环境,美化城市景观,消除噪音、净化空气、调节气候以及涵养水源都有着重要的作用。本文通过对邳州市城区行道树的树种及应用现状进行分析,结合阐述行道树树种选择、规划应用的原则,提出了改变当前现状,丰富邳州市城市行道树种的对策和建议。     

Assessing the structure and stability of street trees in Lhasa,China

Street trees can provide important environmental services to residents living in high-altitude cities. Nevertheless the performance of street trees in this unique environment is largely unknown. This article examines the impact of high-altitude environments on the growth of street trees through a case study in Lhasa, China. The structure, species composition, and health condition of street trees in Lhasa were surveyed using a representative sampling approach. The history of street tree programs and factors that affect the health of street trees was also analyzed. The results showed that there were 24 species and cultivars in 2032 sampled street trees. The street tree population in Lhasa contained a significant number of small trees, which was due to the large-scale planting program initiated in recent years. The street tree population in Lhasa was not very stable due to the uneven age distribution. The health conditions of street trees were affected by climatic factors as well as by management practices. We concluded that unfavorable environmental conditions in high-altitude cities may affect the sustainability of street tree populations to some degree but that human management of the street tree population is a more significant factor.     

城镇密集区行道树结构特征及发展对策研究

行道树绿化是城镇密集区绿化的骨干,反应城市的景观风貌.对行道树结构特征研究分析,可以为今后城镇密集区绿化发展提供有益的指导、建议.现以成都市为例,选取城镇密集区内20条特色街道,参考多度、频度、重要值、常绿落叶树种比及乡土外来树种比等指标,对行道树种类、数量、生长情况进行分析研究.结果表明:成都市城区内行道树树种单一,常绿树过多,乡土树种开发利用不够等,需要进一步优化行道树树种格局,增加生物多样性,丰富城市景观.     

徐州市城市行道树现状浅析

通过对徐州市城市行道树应用现状进行调查分析，了解到品种单一、地方特色不足是徐州市行道树的主要特点，同时提出改变当前行道树现状，丰富徐州市绿化树种的对策与建议。     

Google Street View shows promise for virtual street tree surveys

Geospatial technologies are increasingly relevant to urban forestry, but their use may be limited by cost and technical expertise. Technologies like Google Street View™ are appealing because they are free and easy to use. We used Street View to conduct a virtual survey of street trees in three municipalities, and compared our results to existing field data from the same locations. The virtual survey analyst recorded the locations of street trees, identified trees to the species level, and estimated diameter at breast height. Over 93% of the 597 trees documented in the field survey were also observed in the virtual survey. Tree identification in the virtual survey agreed with the field data for 90% of trees at the genus level and 66% of trees at the species level. Identification was less reliable for small trees, rare taxa, and for trees with multiple species in the same genus. In general, tree diameter was underestimated in the virtual survey, but estimates improved as the analyst became more experienced. This study is the first to report on manual interpretation of street tree characteristics using Street View. Our results suggest that virtual surveys in Street View may be suitable for generating some types of street tree data or updating existing data sets more efficiently than field surveys.     

Diversity of street tree populations in larger Danish municipalities

Healthy and sustainable tree populations require a high diversity of genera and species. This study examined the occurrence and contents of tree inventories in Denmark's 30 largest municipalities. 59% of the municipalities had a tree inventory for street trees, but only about half of these were complete and updated. Only one municipality had a registration for trees other than street trees. Based on data from the tree inventories, the diversity of road side trees was analyzed at genus level and species level. A total of 82,072 street trees are part of the study. 11 different genera account for 92% of the total street tree stock, and 2–6 genera account for 40–80% of the street tree stock in the individual municipalities. Tilia was the most dominating genera (26%). 12 species account for 73% of the total street tree stock. The 6 most common species account for almost 50% of the total tree population. The species representing the largest numbers were Tilia × europaea (12%), Acer platanoides (10.9%), Platanus × acerifolia (7.2%), Tilia cordata (7.2%), Fraxinus excelsior (6.2%) and Sorbus intermedia (5.9%). The four most urbanized municipalities had a surplus of non-native species, but all municipalities apart from one had most street trees belonging to native species. The concluding recommendation of this study is that tree managers need to start working more strategic with their tree stock, in order to reduce the vulnerability, due to potential attacks from pests or diseases and climate change effects. A risk spreading system for the urban tree population is proposed, suggesting that no genera should account for more than 10% and no species for more than 5% of the tree population.     

Tree establishment practice in towns and cities – Results from a European survey

A working group within the European Union funded COST Action E12, “Urban Forests and Trees”, carried out a survey between 1999 and 2001 to study current tree establishment practice in European towns and cities. An extensive questionnaire requesting information on the urban area, selection of tree species, establishment and aftercare practices and the main damaging factors was sent to tree professionals in urban areas in each of 17 countries.Indicators such as the relationship between the urban population and the number of street trees were used to compare urban areas. While most central European cities have a ratio of 50–80 street trees per 1000 inhabitants, the tree density was as low as 20 street trees per 1000 inhabitants for Nice. Often only a few species are planted and this may give cause for concern, since species diversity is considered an important factor in increasing the resilience of the urban tree population to abiotic and biotic stresses.The planting of larger street trees of 20–30 cm circumference, usually with hessian-wrapped rootballs, is becoming increasingly common practice. However, some countries report the use of mostly bare-rooted stock of much smaller trees (less than 12 cm circumference). Establishment costs for street trees range from less than 200 Euro to over 1500 Euro each. Poor site conditions, and impacts such as utility trenching are considered to be major restrictions to healthy tree life. Vandalism affects up to 30%of newly planted street trees in some towns and cities.Overall, the survey reveals large differences in tree establishment and management practices among European cities. There is a need to provide urban tree managers with guidance on good practice for tree selection and establishment based on empirical information. The survey was a first step towards collecting the necessary urban forest information from across Europe.     

Street trees in Bangalore: Density,diversity, composition and distribution

Once renowned as India’s “garden city”, the fast growing southern Indian city of Bangalore is rapidly losing tree cover in public spaces including on roads. This study aims to study the distribution of street trees in Bangalore, to assess differences in tree density, size and species composition across roads of different widths, and to investigate changes in planting practices over time. A spatially stratified approach was used for sampling with 152 transects of 200 m length distributed across wide roads (with a width of 24 m or greater), medium sized roads (12–24 m) and narrow roads (less than 12 m). We find the density of street trees in Bangalore to be lower than many other Asian cities. Species diversity is high, with the most dominant species accounting for less than 10% of the overall population. Narrow roads, usually in congested residential neighborhoods, have fewer trees, smaller sized tree species, and a lower species diversity compared to wide roads. Since wide roads are being felled of trees across the city for road widening, this implies that Bangalore’s street tree population is being selectively denuded of its largest trees. Older trees have a more diverse distribution with several large sized species, while young trees come from a less diverse species set, largely dominated by small statured species with narrow canopies, which have a lower capacity to absorb atmospheric pollutants, mitigate urban heat island effects, stabilize soil, prevent ground water runoff, and sequester carbon. This has serious implications for the city’s environmental and ecological health. These results highlight the need to protect large street trees on wide roads from tree felling, and to select an appropriate and diverse mix of large and small sized tree species for new planting.     

Diversity and distribution of the urban tree population in ten major Nordic cities

In order to have a healthy and sustainable urban tree population, a high diversity of species and genera is needed. This study examined (1) the diversity and distribution of genera and species of urban trees in the Nordic region; (2) the diversity in different sites of the city, distinguishing between street and park environments; and (3) the presence of native versus non-native tree species in urban environments in the Nordic region. The analysis of tree diversity was based on urban tree databases comprising a total of 190 682 trees in 10 Nordic cities – Aarhus and Copenhagen in Denmark; Espoo, Helsinki, Tampere and Turku in Finland; Gothenburg, Malmo and Stockholm in Sweden; and Oslo in Norway. The tree databases for Copenhagen, Espoo, Helsinki, Stockholm and Tampere only record street trees, while the remaining databases also include park trees. Tilia was the most dominant genus in Arhus, Copenhagen, Espoo, Gothenburg, Helsinki, Oslo and Stockholm, while Sorbus was the most dominant in Malmo and Betula in Tampere and Turku. Tilia × europaea was the most common species, comprising 16.0% of the total number of tree species. There was a higher proportion of species in parks than in street environments. The number of non-native species was higher than the number of native species in both street and park environments. However, the number of individuals belonging to native species was higher than the number of non-native individuals in all cities and environments except park environments in Arhus. The concluding recommendation from this study regarding greater diversity of genera and species is to exploit local experiences of rare species from local urban tree databases. After appropriate evaluation, urban tree planners can evaluate these rare species in larger numbers for e.g. street environments, where the need is greatest.     

The ecosystem disservices of trees on sidewalks: A study based on a municipality urban tree inventory in Central Italy

Urban green infrastructure, including street trees, plays a key role in providing ecosystem services to urban residents. However, to fully understand the effective role of trees in the urban context, it is also necessary to evaluate the disservices that they can produce in the development of their functions if not managed in an adequate and integrated way. This contribution aims to demonstrate an approach to assess three disservices (pavement damage, aesthetic damage, likelihood of tree failure) of street trees at the municipal level, starting from the existing municipal tree inventory. In this case study, from the street tree population, a sample of approximately 5% of the trees was drawn by stratified random sampling, where the strata were composed of groups of tree species. In particular, a sampling scheme is adapted in which the probability to select a tree in the sample is greater for bigger trees, under the assumption that the bigger the trees the greater are the disservices caused. In this way, a greater precision of the estimates of the considered disservices for the population of urban trees is expected. The results show a high variability of disservices provision among species groups. The results also confirmed a positive correlation between the considered disservices and tree diameter at breast height, while other tree attributes such as total height and crown diameter were found to be positively related only to pavement damages. Finally, severe pruning can lead to a high level of the aesthetic and functional disservices even for shorter and younger street trees.     

周口市街道行道树的应用现状及对策分析

主要分析周口市街道行道树应用存在的问题,表现为:树种选择缺乏科学性,特色不明显;树种选择缺乏长远性,速生树种多、慢生树种少;行道树开发利用的研究工作滞后;行道树的种植和养护水平有待提高.并针对以上问题提出一系列的相应对策.