共查询到20条相似文献，搜索用时 31 毫秒
1.
Cities in the Latin America and Caribbean (LAC) region and around the world are setting long-term greening goals that include planting more trees and increasing green cover. Research in LAC cities has mainly focused on biodiversity and vegetation, with little understanding of the mechanisms underlying the decisions through which stakeholders achieve urban greening. Exploring stakeholders’ views about urban forest management and governance can provide us with an opportunity to identify needs and research gaps for urban greening and urban forestry in LAC. To our knowledge, there has never been a region-wide empirical study to capture these stakeholder views. Here we explore how stakeholders working in urban forestry in LAC, including governmental, and non-governmental professionals, define urban forests, and view management and governance issues as well as educational opportunities. We used an online survey based on a combination of open- and closed-ended questions. The survey was delivered to participants at the first two regional conferences on urban forests in LAC organized by the United Nations. We collected 91 responses from stakeholders working in 50 different cities of varying population sizes across 6 LAC bioregions. Most respondents considered parks, planted green corridors, street trees, and remnant forests in urban and peri-urban areas as components of urban forests. Stakeholder views on management and governance were divided in two distinct perspectives, one dominated by public participation issues, and another one related to operational issues. Most respondents considered operational and management tools for urban forests to exist in LAC cities, but they disagreed on the existence of inventories, long-term strategies, and ways for the public to engage in urban forestry. Responses also revealed that some educational opportunities, such as arboricultural certification, are still relatively scarce and in high demand in the region. This study provides a regional baseline and first insights into a more diverse view of urban forestry which could be enriched with more empirical studies in the future. 相似文献
2.
Despite the many benefits of vegetation in urban settings, inner-city areas often are sparsely vegetated or devoid of plants. This suggests substantial opportunity for improving provision of ecosystem services in densely populated areas, through retrofitting of urban environments with plants. This paper introduces the concept of ‘biological potential’ – the pragmatic potential for urban areas to be retrofitted with suitable green infrastructure.This paper demonstrates a method for making a quantitative, spatially explicit estimate of the biological potential of walls in the CBD of Melbourne, Australia. The results of this study represent an estimate of how much wall space could be home to green façade plants (i.e. creepers and climbers). The methodology is also spatially explicit – it estimates where the best locations in the city are for this kind of greening, recognising that not all walls have suitable physical characteristics or local microclimates. Employing a combination of GIS and microclimatic modelling techniques, this study estimates that over 16 ha of wall space has potential for greening in Melbourne's CBD, with 1.8 ha showing optimal characteristics. 相似文献
3.
After years of decline and neglect, low woodland types based on coppice management experience renewed interest. Substantial research has demonstrated the potentials of coppice for biomass production and for nature conservation, and coppices are increasingly being suggested for urban situations. Yet, our understanding of the more social aspects of coppice woodlands in modern urban situations is limited. Against this background, this contribution classifies coppice management systems as a basis for identification of social aspects of coppices and their potential use in contemporary urban forestry. Based on this classification, the social perspectives and potential niches for urban coppices are discussed, while lines of research are suggested which will support the development of a thorough and up-to-date knowledge base, against which the social merits of urban coppice woodlands can be critically evaluated. 相似文献
4.
We examine the potential role of perennial woody food-producing species (“food trees”) in cities in the context of urban sustainable development and propose a multifunctional approach that combines elements of urban agriculture, urban forestry, and agroforestry into what we call “urban food forestry” (UFF). We used four approaches at different scales to gauge the potential of UFF to enhance urban sustainability and contribute to food security in the context of urbanization and climate change. First, we identified 37 current initiatives based around urban food trees, and analyzed their activities in three categories: planting, mapping, and harvesting, finding that the majority (73 %) only performed one activity, and only 8 % performed all three. Second, we analyzed 30 urban forestry master plans, finding that only 13 % included human food security among their objectives, while 77 % included habitat for wildlife. Third, we used Burlington, Vermont as a case study to quantify the potential fruit yield of publicly accessible open space if planted with Malus domestica (the common apple) under nine different planting and yield scenarios. We found that 108 % of the daily recommended minimum intake of fruit for the entire city’s population could be met under the most ambitious planting scenario, with substantial potential to contribute to food security even under more modest scenarios. Finally, we developed a Climate–Food–Species Matrix of potential food trees appropriate for temperate urban environments as a decision-making tool. We identified a total of 70 species, 30 of which we deemed “highly suitable” for urban food forestry based on their cold hardiness, drought tolerance, and edibility. We conclude that substantial untapped potential exists for urban food forestry to contribute to urban sustainability via increased food security and landscape multifunctionality. 相似文献
5.
随着现代城市绿化水平的不断提升,观赏果树被越来越多地运用到城市绿化中。对观赏果树在承德绿化中的应用作了阐述;对承德市绿化中发展果树类的优势及问题做了分析;对观赏果树在城市绿化中的发展提出了一些建议。 相似文献
6.
G.H. Stoffberg M.W. van Rooyen M.J. van der Linde H.T. Groeneveld 《Urban Forestry & Urban Greening》2010,9(1):9-14
Amelioration of global warming presents opportunities for urban forests to act as carbon sinks, and thereby could possibly be included in the potential future carbon trade industry. The City of Tshwane Metropolitan Municipality provided a strategy in 2002 to plant 115,200 indigenous street trees in the period 2002–2008. These trees hold a monetary carbon value in their potential future growth. In order to calculate the carbon sequestration potential, the growth rates of Combretum erythrophyllum, Searsia lancea and Searsia pendulina were determined. Combined species growth regressions of C. erythrophyllum–S. lancea and S. lancea–S. pendulina are also presented. Combretum erythrophyllum has the fastest growth rate while those of S. lancea and S. pendulina are slower. The results from growth regression relationships were used in a generic allometric biomass regression to calculate the carbon sequestration rate of each species, which was extrapolated to determine the total quantity of carbon to be sequestrated by the street trees over a 30-year period (2002–2032). It is estimated that the tree planting will result in 200,492 tonnes CO2 equivalent reduction and that 54,630 tonnes carbon will be sequestrated. The carbon dioxide reductions could be valued at more than US$ 3,000,000. But this estimate should also be viewed in the context of the limitations presented in this study. This illustrates that when future carbon trade becomes operational for urban forests these forests could become a valuable source of revenue for the urban forestry industry, especially in developing countries. 相似文献
7.
选用北京市区优良城市绿化彩色树种,包括紫叶稠李（Prunus wilsonii）、春雪海棠（Malus‘Spring snow’）、王族海棠（Malus‘Royalty’）、火焰卫矛（Euonymus alatus‘Compacta’）,银白槭（Acer saccharinum）,用分光光度计法测定色素含量,探讨与其叶片颜色的关系。在不同季节同一地点进行采样测定,发现花青素在紫（红）色系彩叶植物叶片的呈色中占主导作用;叶片颜色随着温度的变化而变化,是影响叶片颜色的最主要外界因素之一;在季节的变化过程中植物叶片的色素含量也呈现规律性变化。结果将为进一步研究彩叶植物的成色机理提供依据,为城市绿化品种推广作为参考。 相似文献
8.
Photorealistic visualisation of urban greening in a low-cost high-density housing settlement, Durban, South Africa 总被引：1，自引：0，他引：1
Apartheid housing policies of the pre-1994 South African government, and the low-cost high-density housing programmes of the post-1994 government, have given rise to numerous urban environmental problems, some of which could be addressed in a cost-effective and sustainable manner through urban greening, while simultaneously promoting biodiversity. Public participation in the planning of urban greening has been identified as being of vital importance, without which urban greening projects run a high, and expensive, risk of failure. Previous studies indicate that the greening priorities of residents in low-cost high-density housing settlements may differ considerably from those of managers and experts tasked with the protection and extension of the natural environment resource base. A system of participatory decision support is therefore required to reconcile the greening requirements of the community, and the ecological benefits of biodiversity. If language, literacy, map literacy and numeracy difficulties are to be avoided, and a sense of place or belonging is to be invoked, such a participatory decision support system should, ideally, be visually based and capable of generating realistic eye-level depictions of the urban landscape. New computer-based landscape visualisation applications, which can directly utilise geographical information systems (GIS), computer-aided design (CAD) and Digital Elevation Model (DEM) data to produce detailed photo-realistic viewsheds, were deemed better suited to the task of visualising urban greening than existing GIS-based mapping systems, CAD and traditional landscape visualisation methods. This paper examines the process of constructing a 3D computer model of the Mount Royal low-cost high-density housing settlement, situated in the eThekwini Municipality, KwaZulu-Natal, South Africa. Visualisations including terrain, natural features, indigenous vegetation, houses and roads were produced and submitted, with a questionnaire, to experts from different disciplines, Mount Royal residents and neighbours. Results from the expert survey indicate moderate support for visualisation in professional decision-making. Both experts and residents expressed strong support for the accuracy and credibility of the visualisations, as well as for their potential in a participatory decision support system. 相似文献
9.
The frequency and intensity of heat stress events globally have increased over the past 20 years. Climatic modeling predicts that this trend will continue throughout the 21st century, with the global land area experiencing heat waves doubling by 2020 and quadrupling by 2040. Due to the reflective nature of buildings and infrastructure, heat temperatures tend to be higher within urban landscapes than outlying rural areas. Heat stress influences processes from the molecular level to whole-tree biology. At the leaf level, photosynthesis is reduced, photo-oxidative stress increases, premature leaf abscission occurs, and the growth of leaves decreases. Growth decreases at the whole tree level, and biomass allocation between roots, shoots, leaves, and branches is altered. When drought and heat stress are combined, detrimental effects are considerably enhanced and, without irrigation, can quickly lead to tree death. There have been few studies regarding the heat tolerance of urban tree species. However, there is evidence of genetic variation in heat tolerance between and within species within forestry, which could be essential to exploit for urban trees. Understanding the mechanisms of tree physiological, biochemical, and molecular responses to extreme heat events is also necessary for understanding how urban tree species will be affected by climate change. 相似文献
10.
Globally, there is growing recognition of the potential of road verges to contribute to urban greening and ecosystem service provision, beyond their original functions of utility provision and public access. Numerous, diverse stakeholders are involved in their management, yet their shared and diverging perspectives on verge greening are poorly understood. This research examined the perspectives on road verge greening by 30 respondents from eight stakeholder groups from the Perth Metropolitan Area, Australia. Stakeholders spanned local and state governments, developers, peak bodies, utility providers, environmental consultants, verge treatment providers and urban greening advocates. Semi-directed interviews and Likert scales were used to assess respondents' perspectives and perceived importance of urban verge functions and ecosystem services, risks and challenges associated with verge greening, and preferred verge vegetation composition. The most important ecosystem services for all stakeholders were temperature regulation (through the provision of street trees), those associated with water management and aesthetically interesting streetscapes. Perceived challenges included limited knowledge for the management of native species verges and streetscapes, organisational costs for verge managers and utility providers, and the need to engage with multiple local government authorities with widely varying management and financial valuation of verge vegetation. Stakeholders’ preferred verge reflected diverse uses, local characteristics, and was climate and water resilient (particularly ‘waterwise’). A majority of stakeholder groups felt greater attention to the ‘understorey’ of the ‘urban forest’ was warranted. An emerging perspective across four stakeholder groups identified the potential for verges to grow a local ‘sense of place’, through plantings emphasising local native species and highlighting local Whadjuk Noongar seasons. These findings support policies and programmes associated with urban greening, and assist in navigating the contestation often associated with new or transformative uses of land at the public-private interface. 相似文献
11.
The information of urban tree species resources is of vital significance to the planning and design of urban green spaces. Tree organs, such as the bark are used as the primary features of identifying tree species. However, traditional tree identification methods need to consume a lot of manpower and time costs. In addition, the application of machine image recognition technology to tree species recognition still has problems such as heavy data preprocessing workload, small number of tree species images, uneven distribution of categories, and low recognition accuracy. In order to promote the intelligent management of urban forestry and solve the above problems, it is necessary to establish an automatic image recognition model for urban greening tree species. We captured bark images of 21 urban afforestation tree species in their natural environment and constructed a dataset that was divided into a train set, validation set, and test set in the ratio of 7:1:2. Combining Channel Attention Module (CAM) with algorithms such as Spatial Pyramid Pooling (SPP) and Mixed Depthwise Dilated Convolutional Kernels. The core algorithm is Mixed Convolution Kernel (MK), and a CAMP-MKNet Convolutional Neural Network (CNN) is constructed as a bark image classification model for urban greening tree species. The overall accuracy of the generic models ranged from 41.06% to 82.03%, whereas the overall accuracy of the experimental CAMP-MKNet model was 84.25%, with lower prediction cost. Our study shows that the CAMP-MKNet CNN model with better prediction performance and computational cost and can provide crucial insights and technical support for developing automated urban tree species image recognition systems. 相似文献
12.
Green roofs provide a number of different urban ecosystem services (UESS), e.g. regulation of microclimate, support of air quality improvement, or stormwater retention. To estimate the spatial variation of green roof UESS across an urban area, a GIS-based mapping and spatial analysis methodology was established and applied to the city of Braunschweig, Germany. Based on the analysis of available geodata, in a first step, a quantity of 14,138 rooftops in the study area (14% of all buildings) was found to be generally suitable for greening. This resulted in a green roof area of 3 km2. Based on criteria such as roof slope and minimum roof size, nearly two-thirds of these buildings (8596 buildings, 8.6% of total number of buildings) were categorised ‘appropriate’ for greening and subject to green roof UESS analysis.The spatial distribution of green roof UESS was estimated based on the categories thermal urban climate, air quality, stormwater retention and biodiversity. Due to their potential benefits in the four UESS categories an overall assessment resulted in a number of 867 roofs (0.9% of total number of buildings) categorised as ‘high benefit’ from rooftop greening. Another 3550 buildings (3.5%) and 4179 buildings (4.2%) were defined as ‘moderate benefit’ and ‘low benefit’, respectively. The inner city area of Braunschweig appears as a hot-spot of green roof UESS, i.e. higher percentage of ‘high benefit’ green roofs in comparison to residential areas. The proposed method is a simple but straightforward approach to analyse urban green roof UESS and their spatial distribution across a city but it is sensitive to the quality of the available input geodata. 相似文献
13.
The creation of green rooftops is an important method for mitigating heat build-up in urban rooftop environments because they lower the sensible heat flux over the rooftop and conductive heat flux into the building. We propose a model for assessing thermal mitigation effects through a hydroponic urban greening system based on heat balance. We conducted an experiment with two different rooftops at two study sites, which were monitored for two months in two different years. Each rooftop was divided into two areas: one bare, the other covered by the hydroponic urban greening system. Parameters measured in both areas were air temperature, surface temperature, and conductive heat flux. The data were analyzed using three thermal mitigation indices. However, it was difficult to show a uniform relationship between the latent heat flux and mitigation indices during the period of analysis. This suggests it would be necessary to include factors such as latent heat flux, conductive heat flux, and water heat storage flux to assess the thermal mitigation effect. Our research indicated that the composition of heat balance terms could estimate thermal mitigation effects in the green roof area independent of the year. The results suggest a principle for assessing the mitigation effects of urban greening on the thermal environment. 相似文献
14.
The near-to-nature urban forestry concept and practices are widely recognized for urban greening, urban ecosystem restoration, urban greenspace management for biodiversity conservation and ecosystem services provision. However, the regeneration and succession of urban vegetation are rarely studied due to the complex settings of the urban environment. To this end, we conducted a large-scale field investigation in the metropolitan area of Beijing, China to explore the spatial variations in plant species composition and diversity in soil seed banks, and their similarity to the aboveground vegetation to assess the potential of urban plant regeneration. Overall, 657 vegetation and soil sampling plots from 219 grids, measuring 2 km × 2 km each, were investigated within two perpendicular 10 km wide transects running across the urban center in north-south and east-west directions within the 6th Ring Road of the city. We recorded a total of 102 plant species in soil seed banks, including 13 tree species, 10 shrub species, and 79 herb species. We found that the soil seed bank species diversity and its similarity to that of the aboveground vegetation communities decreased significantly with the urbanization intensity. Higher urbanization intensity is typically associated with increased human management and a reduction in Greenspace Area (GSA). Soil seed bank species richness increased significantly when GSA exceeded 45 % and the similarity of species composition and diversity between soil seed banks and aboveground vegetation communities was the highest in forest parks. This suggests that habitats under forest park management are more conducive to plant regeneration. Soil seed bank species diversity first increased and then decreased significantly with increased distance to the city center, whereas the species similarity between the soil seed banks and the aboveground vegetation communities showed little change with the ring roads going out. The results of this study have important implications for further understanding the potential for urban vegetation regeneration and sustainability, which have significant implications for urban biodiversity conservation and restoration. 相似文献
15.
Autumn phenology is an important part of the tree growing season that is still poorly understood. In addition to the environmental factors that might affect its timing, there are artificial effects introduced by modern society that could interfere with it, such as the increasing use of artificial light to illuminate urban nights. This study investigates the relationship between outdoor public lighting and leaf senescence of Platanus x acerifolia that constitutes with more than 4000 individuals, and 6% of public greening in Florence, Italy. The difference in autumn phenology under two lighting conditions was assessed by analysing data collected in a real context, using a presence-absence protocol of green leaves on 283 trees during leaf fall season from 2014 to 2017. Trees were classified in two groups of different light exposure. In 2016–2017, data were also collected at Cascine park, the main green area within the city and darker than the monitored sites. According to the analysis, the percentage of trees with green leaves under luminaires was significantly higher than trees far from the luminaires, for all sites from mid-December to the end of January, and this effect was enhanced during 2016–2017 which was characterised by a colder winter. In the same year, the period of absence of green leaves at Cascine started at least 20 days earlier than the other sites. These findings should be taken into consideration by scientists because artificial light could affect autumn phenology and therefore the length of the vegetative season, and by urban greening and light managers during the design and management of public green spaces. Moreover, the presence-absence protocol proved to be suitable for collecting observations because it was easy to perform in a real context. 相似文献
16.
Peter Bentsen A. Christian Lindholst Cecil C. Konijnendijk 《Urban Forestry & Urban Greening》2010,9(4):273-280
Since its launch in 2002, the journal Urban Forestry & Urban Greening (UFUG) has welcomed research from a range of disciplines and perspectives, with the aim of enlarging the body of knowledge on topics related to use, planning, design, values, and establishment of urban and peri-urban woody and non-woody vegetation. Here, we present a review of all scientific contributions published in the journal's first eight volumes (159 in all), and provide suggestions for improving the future content of UFUG. A framework for review was developed based on the journal's Aims and Scope, which set out the journal's ambitions related to, e.g. scientific diversity and international scope. The journal's achievements until now were assessed by analysing all scientific contributions for type of paper, type of green space, research theme, type of science, research method(s), and nationality of first author.Our review shows that the large majority of the contributions have been research papers. Regarding type of green space studied or considered, the overall green structure, woodland, as well as trees have been well covered, with parks having been studied much less. When looking at research themes, UFUG's envisaged variety of topics is evident. The physicality of green space, green space management, and the experience of green space have been given most attention, with less attention for valuation and governance aspects. Most UFUG contributions have been rooted in the social or natural sciences, with about one fifth of all papers involving more than one discipline, and the humanities being almost absent. Scientific diversity can also be seen from the wide range of research methods applied. The journal lives up to its international scope, with a large number of countries present. However, most first authors have been based in Europe and North America, with the USA and Scandinavia being particularly dominant.For the further development of the fields of urban forestry and urban greening, it is important that UFUG helps foster scientific debate and advancement. This will require greater focus on review papers, meta-studies, short communications, and on theoretical and methodological issues in general. Thematically, several relevant topics within urban forestry and urban greening, such as organisational aspects of green space management, could be given more attention. Also, normative issues such as the common understanding of ‘green’ as something inherently ‘good’ need to be addressed more critically. 相似文献
17.
Assessment of the amount of carbon sequestered and the value of ecosystem services provided by urban trees requires reliable data. Predicting the proportions and allometric relationships of individual urban trees with models developed for trees in rural forests may result in significant errors in biomass calculations. To better understand the differences in biomass accumulation and allocation between urban and rural trees, two existing biomass models for silver birch (Betula pendula Roth) were tested for their performance in assessing the above-ground biomass (AGB) of 12 urban trees. In addition, the performance of a volume-based method utilizing accurate terrestrial laser scanning (TLS) data and stem density was evaluated in assessing urban tree AGB. Both tested models underestimated the total AGB of single trees, which was mainly due to a substantial underestimation of branch biomass. The volume-based method produced the most accurate estimates of stem biomass. The results suggest that biomass models originally based on sample trees from rural forests should not be used for urban, open-grown trees, and that volume-based methods utilizing TLS data are a promising alternative for non-destructive assessment of urban tree AGB. 相似文献
18.
Arbor Day, or Week, is a well-established greening initiative worldwide, focusing on tree planting and the benefits thereof. Frequently most effort is targeted at institutions such as schools and community groups. Yet there has been limited assessment of the success of Arbor Day, or Week, activities both at the schools, or the wider dissemination in neighbouring communities and suburbs. The objective of this study was to determine the influence of school-based Arbor Week activities on learners’ home-based practices regarding tree planting and urban forestry. Learners from three schools in Grahamstown South Africa, with good Arbor Week participation, were assessed on their tree planting knowledge. The learners’ parents were also interviewed to determine whether the information obtained by the learners at school was taken home. A control group consisting of people with no children or very young children was also assessed. This study found that Arbor Week activities were, for the most part, successfully taught in the case study schools, and most of the learners stated that their knowledge of trees and their benefits came from their school activities. However, many learners could not remember the activities in which their schools partook the previous year. Whilst most learners were aware of the importance of trees, few had encouraged tree planting at home. However, over one-fifth of adults claimed that their knowledge of the benefits of trees was as a consequence of Arbor Day activities when they were young. Numerous constraints to tree planting were provided by learners and both the adult groups, the two most frequent being limited space and falling leaves making their yards untidy. External organisations should become more actively involved and provide much needed support systems if greening initiatives are to reach the wider community. 相似文献
19.
Liveability is an important component of the sustainable urban environment, especially in residential neighbourhoods. This study presents a comparison in perceived liveability between residents living in two very different locations, Tehran, Iran and Tartu, Estonia, using a questionnaire survey (n = 102). The image-questionnaire was used to measure residents’ response towards environmental factors and to examine the relationships between the attributes of residential neighbourhoods and perceived liveability. Statistical analyses were performed to analyze the data collected from the survey. The results showed that the neighbourhood liveability was positively influenced by proportion and scale of the spaces, amount of private green areas, street character, amount of public greenery, the variety of building form, the mix of buildings from different periods, perceived crowding and social density. The study demonstrated that residents can assess the factors and that the approach worked in two contrasting locations. The results also showed a great deal of similarity in preference, although this was not the main aim of the study. The approach has potential to be incorporated into participatory urban planning models. 相似文献
20.
Human preferences for the species in urban greening have greatly facilitated the spread of non-native species, resulting in the homogenization of urban plant communities across spatial scales. We selected 11 major cities along the Yangtze River in China and examined the species composition in their urban plant communities. We found that China’s urban plant communities are becoming homogenized, as urban communities of different cities are highly similar to each other despite the geographical separation. Meanwhile, these artificial communities we investigated have diverged greatly from the natural communities at both the city and the geographic scale. We recorded a total of 91 woody species that have been used in urban greening in all 11 cities. Of those species, 27% were cultivars and introduced species, and 25% were being used outside of their native distribution ranges in China. This may be explained by the market and urban planners who tend to favor greening plants that are highly profitable and have aesthetic ornamental traits, rather than spending time introducing and acclimatizing the native species in each city. Given the current trend of homogenization, measures that recognize the importance of native species should be emphasized with comprehensive urban planning strategies. 相似文献