即墨市行道树树种的选择

本文首先对即墨市的气候学特点和树种资源进行了阐述,接着分析了即墨市行道树的分布和存在的问题,最后对即墨市行道树树种的选择提出了建议。     

浅议南通市城市行道树树种选择

分析江苏南通市城市绿化行道树树种立地条件,分别从土壤、气候条件、耐修剪、生长快等方面提出城市行道树树种选择设想,以丰富道路绿化景观,提高城市绿化水平。     

邳州市城郊行道树树种选择原则与对策

邳州城郊道路绿化面积达到300万m2,水杉路、银杏路、香樟路、女贞路,一树一景、景景生辉独特的行道树风景彰显了邳州的城市魅力和文化底蕴。     

师宗县城区行道树乔木树种现状调查与分析

调查师宗县城区主要市政不同等级的24条道路行道树乔木树种的应用现状,共计有18种行道树种,隶属12科18属。树种应用频度最高为香樟,应用频度为50。树种重要值排前十为香樟、雪松、滇朴、银杏、法国梧桐、圆柏、木莲、复羽叶栾树、毛果含笑、棕榈。通过树种生活型比较分析,常绿树与落叶树比例为7︰2。结果表明,师宗县行道树植物生活型比例失衡,行道树应用树种种类单一,根据师宗县行道树现状,结合城市特点,提出了师宗县行道树的应用提出建议。     

萍乡市行道树现状分析与初议

通过街道实地走访、目测步测及航拍等方式,调查分析萍乡市老城区及部分新城区街道行道树树种组成、生长表现及周边环境。结果表明:萍乡市行道树以乡土树种樟树为主,广玉兰为次,树种单调,常绿树和落叶树比例严重失衡,季相景观变化弱,生长表现有好有坏,参差不齐,行道树周围环境有待改善。为解决萍乡市行道树应用上的问题,应积极筛选增加可用的行道树树种,加强养护管理,在全面建设海绵城市同时,也需要注重树种规划与设计。     

行道树种的合理选择与应用

纵横交错的街区道路构筑了城市的内部运营机制四通八达的城郊公路加强了城市的外部连接功能．而行道树的选择应用．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。     

延吉市行道树的选择与栽植技术

通过调查吉林省延吉市行道树的栽植现状,对行道树的选择原则、可选择树种以及对行道树的检疫、采购与栽植等进行探讨,并提出栽植过程中需要注意的相关技术要求,为有效推进城市景观生态化、园林化和森林化工作提供科学参考。     

北方地区行道树的选择与应用

文章对北方地区行道树的选择,注意事项,和北方地区常用的行道树种进行了探讨。     

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。     

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.     

Potential of Internet street-view images for measuring tree sizes in roadside forests

Tree size censusing is essential for evaluations of trees and forests, but traditional field surveys are both time- and labor-intensive. Here, we discuss the use of panoramic 360-degree street views available on the Internet for censusing of roadside trees in urban regions. Use of scale-independent, fixed-sized street objects as recalibrating meters in tandem with imagery software enabled street-view images to be used effectively in the remote measurement of diameter at breast height (DBH), tree height, underbranch height, and canopy projection size. Comparison of four independent meters determined that stem limewhite-related meters (used for tree disease and bark-freeze injury control; usually 1.3 in height throughout China) had greater precision than road curb height, lane width, and traffic line width meters. The limewhite meter’s precision was slightly lower than those of the meters in combination (i.e., when at least three of the abovementioned meters were used for the same tree measurement), but no statistically significant differences were detected between the limewhite and combined meters (p > 0.05). In contrast, the road curb height, traffic line width, and lane width meters all had significantly lower precision. The highest levels of precision were 92%, 87%, and 80% for DBH, height (tree height and underbranch height), and tree canopy size measurements, respectively. Empirical recalibration of the image-based measurements did not improve data precision with reference to field surveys (p > 0.05). Moreover, similar results were obtained regardless of individual users, and repeatability for DBH measurements (r² > 0.92), and maximum differences among individual users were 0.6–1.9 cm for DBH (averaged at 22 cm) and 8–50 cm for underbranch height (mean value at 8 m). Labor costs and time needed for this approach were one-thirtieth to one-tenth those required for field surveys. Thus, the use of street-view images represents a more resourceful approach to assess forest ecological services.     

Perception and preference of trees: A psychological contribution to tree species selection in urban areas

Trees can enhance human mental and physical well-being in urban environments. However, the tree benefits in urban planning are insufficiently recognised, and there is little knowledge on the tree characteristics that are relevant to humans and how they are evaluated. This paper presents perceptual tree parameters and their relation to human preferences. In study 1, participants sorted 24 tree images by perceived similarity. Hierarchical cluster analysis and multidimensional scaling (MDS) revealed the distinction between conifers and deciduous trees, crown shape, the two-dimensional crown size to trunk height ratio and the crown density as important to humans. In study 2, participants rated the trees based on their preferences. Multiple linear regression analyses showed that a high two-dimensional crown size to trunk height ratio and a high crown density predicted deciduous tree preferences. These findings are discussed in light of the savannah hypothesis and the Gestalt grouping principle of closure. In the task of tree selection and placement for urban areas, the identified perceptual tree parameters may allow for achieving a coherent overall picture with a simultaneous increase of tree species richness. Thus, urban landscape planning can apply the presented findings for increasing ecosystem health and residential satisfaction.     

Assessing the species diversity and vulnerability of urban tree populations in the London borough of Westminster

The level of tree species diversity in urban tree populations can have serious implications for urban forest resilience and has a direct impact on ecosystem functioning at the local level. Few studies have measured the relationship between tree species diversity and vulnerability in UK urban forests. This study analysed the species composition, species diversity and the vulnerability to pests and diseases of 10,149 public trees in the London borough of Westminster across three land use types: housing, parks, and highways. Tree species diversity was significantly different across these land use types (Shannon’s diversity index (H) was 2.47 for housing sites, 1.63 for parks and 0.83 for highways) and we found that higher diversity appears to result in reduced vulnerability, evidenced by negative correlations between tree species diversity and susceptibility to pests and diseases. A stronger negative correlation was found between vulnerability and species richness than between vulnerability and Gini-Simpson’s diversity index. Our study reinforces the role of biodiversity indices in establishing and monitoring baseline levels of UK urban tree diversity. Our findings may inform future tree planting projects, help to ensure that development does not negatively affect urban tree diversity and inform proactive strategies for urban trees to contribute to wider biodiversity conservation.     

Long-term tree survival and diversity of highway tree planting projects

Long-term, multi-decade research on planted tree survival in urban settings is sparse. One understudied urban environment is highway rights-of-way (ROW), lands adjacent to high-speed, unsignalized roadways. We conducted a re-inventory of tree planting cohorts in northern Illinois, U.S. on a 48 km-long highway near Chicago which were 10-, 21-, and 30-years old to evaluate long-term patterns of survival and diversity. Using each randomly selected planting site along the highway as a unit of observation and analysis, we compared the number of trees documented in record drawing to the number of trees currently alive to determine percent survival. We evaluated 224 planting sites which originally contained 2944 trees and collected data about the planting site location. For the oldest cohort, 26% of trees were still alive in 2018 (median survival by species = 16%, Q1 = 0%, Q3 = 48%), while 31% of the 21-year-old cohort (med. = 6%, Q1 = 0%, Q3 = 47%) and 86% of the 10-year-old cohort were still alive (med. = 85%, Q1 = 74%, Q3 = 96%). The survival of the 21- and 30-year-old cohort matches urban tree survival estimates by other researchers, while the 10-year-old survival is higher than expected. The only planting location characteristic that significantly affected survival was traffic islands (areas between the highway and entrance/exit ramps). Species with low drought tolerance were less likely to be alive for the 30-year-old cohort. Waterlogging tolerant species were more likely to be alive in the 10-year-old cohort. Since some species in the 21- and 30-year-old cohorts had very low survival, the tree species richness and diversity s in study areas declined between the initial record drawings and reinventory. This study demonstrates the challenges of maintaining long-term survival and diversity in the highway ROW and emphasizes the importance of species selection.     

Defect-disorder and risk assessment of heritage trees in urban Hong Kong

Heritage trees in a city, echoing factors conducive to outstanding performance, deserve special care and conservation. To understand their structural and health conditions in urban Hong Kong, 30 defect-disorder (DD) symptoms (physical and physiological) subsumed under four tree-position groups (soil-root, trunk, branching, and crown-foliage) and tree hazard rating were evaluated. The surveyed 352 trees included 70 species; 14 species with 233 trees were native. More trees had medium height (10–15 m), medium DBH (1–1.5 m) and large crown (>15 m). In ten habitats, public park and garden (PPG) accommodated the most trees, and roadside traffic island (RTI) and public housing estate (PH) had the least. Tree dimensions and tree habitats were significantly associated. The associations between the 2831 DD and tree-position groups, tree habitats and tree hazard rating were analyzed. Fourteen trees from Ficus microcarpa, Ficus virens and Gleditsia fera had high hazard rating, 179 trees from 22 species moderate rating, and 159 trees from 55 species low rating. RTI, roadside tree strip (RTS), roadside tree pit (RTP), roadside planter (RP) and stone wall (SW) had more moderate hazard rating, and PPG, roadside slope (RS) and government, institutional and community land (GIC) more low rating. Redundancy analysis showed that DD were positively correlated with RTS, RTP, RP and SW, but negatively correlated with PPG, RS and GIC (p < 0.05). The DD significantly increased tree hazard rating and failure potential. Future management implications for heritage-tree conservation and enhancement focusing squarely on critical tree defect-disorder in urban Hong Kong were explored, with application to other compact cities.     

城市行道树抗倒伏关键技术与措施

以沈阳市区行道树为研究对象，研究探讨城市绿地行道树移植后各种导致树木倒伏的因素，并针对行道树倒伏等相关问题，提供切实可行的抗倒伏关键技术，为城市行道树发挥景观生态效果提供技术支持。     

Impervious surface thresholds for urban tree site selection

Impervious surfaces are a ubiquitous urban feature that increase temperature and tree drought stress and are a demonstrated indicator of Acer rubrum L. tree condition and insect pest abundance. We examined the relationship between A. rubrum condition, impervious surface cover, and Melanaspis tenebricosa (Comstock) abundance, a primary herbivore of urban A. rubrum, in eight cities across the southern distribution of A. rubrum. We predicted that the effects of warming, due to impervious surface, would be greater in warmer southern cities than in cooler northern cities. We found that impervious surface was a robust predictor of tree condition, but this effect was not significantly affected by background temperature. Melanaspis tenebricosa abundance was a function of impervious surface and background temperature, with greatest abundances occurring at mid latitudes. Based on these relationships, we developed impervious surface thresholds to inform site selection for A. rubrum throughout the southeastern USA. Planting criteria based on habitat characteristics should maximize urban tree longevity and services provided.     

FlorTree: A unifying modelling framework for estimating the species-specific pollution removal by individual trees and shrubs

Atmospheric pollution is a threatening problem around the world, with tropospheric ozone (O₃), nitrogen dioxide (NO₂) and particulate matter (PM₁₀) among the most harmful pollutants for citizens’ health. Nature-based solutions such as urban trees can cut down air concentrations of these pollutants thanks to stomatal uptake and dry deposition on their canopies and, in addition, uptake carbon dioxide (CO₂) and store carbon in their tissues. Unfortunately, some species emit biogenic Volatile Organic Compounds (bVOCs) that are O₃-precursors leading to air quality deterioration. As a proper selection of species is essential for urban greening, we developed an innovative single-tree model (FlorTree) to estimate the maximum flux of air pollutants. FlorTree considered species-specific parameters, such as tree morphology (height and crown leaf area), leaf/shoot structure, leaf habit (deciduous/evergreen) and eco-physiological responses to environmental factors, for 221 urban tree and shrub species. We applied the FlorTree model to examine i) which are the best species for air pollution removal in the case study of Florence (Italy) and ii) whether the species-specific removal performance is affected by different climate and air pollution conditions in other cities, namely Bucharest (Romania) and Tokyo (Japan). Results suggested that 24 tall trees (mainly broadleaves belonging to Tilia, Acer and Fraxinus genus) may be recommended for Florence due to their large crowns at maturity (50 years old), relatively high stomatal conductance and no bVOCs release. These general characteristics, however, were affected by climatic and pollutant conditions, suggesting that FlorTree must be applied to the local conditions. Therefore, our results demonstrated that FlorTree can be applied in any city for maximizing the air quality improvement by urban trees.     

Survival is not enough: The effects of microclimate on the growth and health of three common urban tree species in San Francisco,California

Urban forest managers must balance social, economic, and ecological goals through tree species selection and planting location. Ornamental trees are often popular in tree planting programs for their aesthetic benefits, but studies find that they have lower survivability and growth compared to larger shade trees. To maximize ecosystem services within these aesthetic preferences, it is important to select species carefully based on their ability to grow in each particular climate. However, little locality-specific and species-specific data exist on urban trees in many regions. This study examines the growth, survival, and vigor of three common ornamental street trees in San Francisco’s three different microclimate zones after over 16 years since planting. While we found over 70% survival for all three species throughout the city, there were significant differences in health and vigor among microclimates for each species, likely due to differences in drought-tolerance. While Arbutus had the greatest proportion of healthy trees in the Fog Belt and Sun Belt zones, Prunus cerasifera had the greatest proportion in the Sun Belt, and Prunus serrulata had the greatest proportions in the Transition and the Sun Belt zones. This species-specific and climate-specific information will better equip urban foresters to target both planting and tree-care of these popular species appropriately to maximize the benefits provided by these street trees while still maintaining a diverse canopy. Finally, we argue that simple survival calculations can mask more complex differences in the health and ability of different urban tree species to provide ecosystem services.