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1.
Cecil C. Konijnendijk Anders Busse Nielsen Jasper Schipperijn Yngve Rosenblad Heldur Sander Mikk Sarv Kirsi Mkinen Liisa Tyrvinen Janis Donis Vegard Gundersen Ulrika kerlund Roland Gustavsson 《Urban Forestry & Urban Greening》2007,6(4):297-309
A review of research and research needs in urban forestry was carried out in Denmark, Estonia, Finland, Latvia, Norway and Sweden during 2005. A questionnaire addressing post-2000 and ongoing research was sent to 146 researchers and generated 76 completed questionnaires. Universities were found to lead urban forestry research, while municipalities headed funding organisations in terms of number of projects funded. Planning, ecological and management aspects were the most common research themes, but socially oriented research also played an important role. The research needs questionnaire was sent to 192 key research actors (assignors, users and researchers), resulting in 63 completed needs assessments. The research themes of ‘urban forest management’, ‘social and cultural values’ and ‘urban forest and green planning’ were prioritised for future research. Comparison of ongoing research and research needs showed discrepancies, as ongoing research does not always cover the same themes identified as primary research needs. Priorities for future research as identified by the research community respective those assigning and using research also differed. Economic assessment of benefits, for example, scored much higher as a need among researchers than other respondents. In terms of present weaknesses in the research ‘infrastructure’, research actors emphasised lack of funding, fragmentation of research and insufficient critical mass. The region's urban forestry research can be enhanced and made more meaningful by strengthening national and international networking within the research community, across disciplines, as well as between researchers and those commissioning and using research. 相似文献
2.
Urban trees store and sequester large amounts of carbon and are a vital component of natural climate solutions. Despite the well-recognized carbon benefits of urban trees, there is limited effort to examine how spatial distribution of carbon density varies across distinctive social, demographic, and built dimensions of urban landscapes. Moreover, it is unclear whether specific aspects of landscape structure and design could help increase carbon densities in urban trees. Here, we produced a fine-resolution carbon density map of urban trees in New York City (NYC) by integrating high-resolution land cover map, LiDAR-derived tree metrics, i-Tree Eco, and field survey data. We then explored spatial variations of carbon density across the gradients of urban development intensity, social deprivation index, and neighborhood age, and we examined the relationships between carbon density, and fragmentation, aggregation, size, and shape of tree canopy cover. We find that carbon stored in urban trees in NYC is estimated as 1078 Gg, with an average density of 13.8 Mg/ha. This large amount of carbon is unevenly distributed, with carbon densities being highest in Bronx and in open parks and street trees. Furthermore, carbon densities are negatively associated with urban development intensity and the social gradient of deprivation. Regarding the impacts of tree morphology on carbon density, our results show that while the amount of tree cover is the most influential factor in determining carbon density, small-sized forest patches and moderate levels of forest edges are also conductive to increasing carbon densities of urban trees. To incorporate urban forestry into developing innovative, effective, and equitable climate mitigation strategies, planners and decision makers need to identify the optimal spatial configuration of urban forests and invest in tree planting programs in marginalized communities. 相似文献
3.
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
4.
Urban street trees provide many benefits to surrounding communities, but our ability to assess such benefits relies on the availability of high-quality urban tree data. While these data are numerous, they are not available in an easily accessible, centralized place. To fill this gap, we aggregated public and private data into a single, comprehensive inventory of urban trees in California called the California Urban Forest (CUF) Inventory. These data are offered to the public (aggregated to ZIP code) via an online data portal, which at the time of publication contained over 6.6 million urban tree records. In this study, we first describe the assembly and utility of the inventory. Then, we conduct the most comprehensive assessment of the diversity and structure of California’s urban forest to date at statewide, regional, and local spatial scales. These analyses demonstrate that California’s urban forests are highly diverse and among the most diverse urban forests in the world. We present a new and intuitive metric of species diversity, the top diversity or TD-50 index, which represents the cumulative number of species accounting for the top 50 % abundance of trees in an urban forest. We used species abundance data from 81 well-inventoried cities to demonstrate that the TD-50 index was a robust metric of diversity and a good predictor of comprehensive metrics like the Shannon Index. We also found that small-statured trees, such as crape myrtles (Lagerstroemia cv.) dominate California’s urban forests. This aggregated inventory of one of the world's largest urban forests provides the data necessary to assess the structure, diversity, and value of California’s urban forests at multiple spatial scales. The inventory’s presentation to the public and the information that can be gained from its analysis can be a model for urban forest management worldwide. 相似文献
5.
Urban paved sites are complex stress environments and when selecting trees for such sites, tree planners must prioritise stress tolerance above aesthetic appeal and functional aspects. This requires detailed information about the tolerance of tree species to environmental stresses, so as to support urban tree planners in selecting a wide range of trees. In Scandinavia there is currently no overview of the extent to which the character of information about stress tolerance and its dissemination in books and papers support urban tree planners in selecting a wide range of species for paved sites. Books on dendrology, literature on plant use in cities, tree nursery catalogues and scientific papers were therefore reviewed. For the review, eight tree species were selected along a gradient representing their intensity of use in Northern Europe. We examined the character of information and assessed it relative to tree planners’ requirements for information to be; contextual, local to Scandinavia, referring to existing plantings in paved sites and recommendations for use of the species in paved sites. The results showed that existing information is piecemeal and that most is either too general (dendrology literature) or too specific or contradictory (scientific literature) to meet the requirements of urban tree planners, while books intended for plant use in cities do not sufficiently integrate the local perspective. Moreover, contextual information local to the Scandinavian region is mainly provided for already much used species. These findings led to suggestions on how future urban forestry and arboriculture research and dissemination efforts in Scandinavia can encourage tree planners to use a greater variety of tree species in urban paved sites. 相似文献
6.
Cities across North America are adopting ambitious goals to grow their urban forests. As existing trees and new planting opportunities are often located on private property, residents’ support and participation is needed in order to meet these goals. However, little research has examined support for municipal urban forestry efforts, including policies specifically targeting residential areas. The objectives of this research are to (1) assess resident’ level of support for common urban forestry policies and (2) determine if there are specific household characteristics associated with different levels of policy support. The objectives are addressed through a statistical analysis of survey responses and a qualitative examination of follow-up interviews with residents in four neighborhoods located in Mississauga (Ontario, Canada). The survey participants and their properties vary in their socioeconomic characteristics, age of development, and urban forest conditions. Our results found that the majority of residents had neutral to very positive attitudes toward common municipal policies encouraging planting and restricting removal of trees, but support levels were lower for the policies than for general statements about desired presence and size of urban trees. Several characteristics are significantly related to level of policy support, including age of household members, education-level, property-level tree density, recent tree planting activity and age of house. Interviews also highlighted residents’ apprehensions about living among tall trees and older resident's concerns with tree maintenance. The results suggest that most residents would be willing partners in urban forestry efforts, with many of these residents already actively planting and maintain trees. However, to increase support and participation rates, different types of trees – including those smaller in stature and ones that require relatively little maintenance – should be part of any planting program to meet the varying needs of households. 相似文献
7.
G.H. Stewart C.D. Meurk M.E. Ignatieva H.L. Buckley A. Magueur B.S. Case M. Hudson M. Parker 《Urban Forestry & Urban Greening》2009,8(3):149-162
Urban forests are increasingly valued for multiple benefits such as amenity, cultural values, native biodiversity, ecosystem services, and carbon sequestration. Urban biodiversity in particular, is the new focus although global homogenisation is undermining regional differentiation. In the northern hemisphere (e.g., Canada and USA) and in the southern hemisphere, particularly in countries like South Africa, Australia, South America and New Zealand, local biodiversity is further impacted by historical colonisation from Europe. After several centuries, urban forests are now composed of synthetic and spontaneous mixtures of native species, and exotic species from around the temperate world (e.g., Europe, North and South America, South Africa, Asia). As far as we are aware no-one has carried out in-depth study of these synthetic forests in any Southern Hemisphere city. Here we describe the composition, structure, and biodiversity conservation imperatives of urban temperate forests at 90 random locations in Christchurch city, New Zealand.We document considerable plant diversity; the total number of species encountered in the 253 sampled urban forest patches was 486. Despite this incredibly variable data set, our ability to explain variation in species richness was surprisingly good and clearly indicates that total species richness was higher in larger patches with greater litter and vegetation cover, and taller canopy height. Species richness was also higher in patches surrounded by higher population densities and closer to very large native forest patches. Native species richness was higher in patches with higher soil pH, lower canopy height, and greater litter cover and in patches closer to very large native forest patches indicating dispersal out of native areas and into gardens. Eight distinct forest communities were identified by Two-Way INdicator SPecies ANalysis (TWINSPAN) using the occurrence of 241 species that occurred in more than two out of all 253 forest patches.Christchurch urban forest canopies were dominated by exotic tree species in parklands and in street tree plantings (linear parkland). Native tree and shrub species were not as common in public spaces but their overall density high in residential gardens. There was some explanatory power in our data, since less deprivation resulted in greater diversity and density, and more native species, which in turn is associated with private ownership. We hypothesise that a number of other factors, which were not well reflected in our measured environmental variables, are responsible for much of the remaining variation in the plant community structure, e.g., advertising, peoples choice. For a more sustainable asset base of native trees in New Zealand cities we need more, longer-lived native species, in large public spaces, including a greater proportion of species that bear fruit and nectar suitable for native wildlife. We may then achieve cities with ecological integrity that present multiple historical dimensions, and sequester carbon in legible landscapes. 相似文献
8.
Canberra, Australia's national capital, is a planned city established on grazing lands in the southern tablelands of New South Wales. Over the past nine decades it has grown into a garden city of 300,000 people. Landscaping was an early priority as much of the chosen site for the city was a treeless plain. Major tree planting began in the 1920's and today the urban forest on public lands contains 400,000 trees from over 200 species in streets and parklands. The species used have changed over time with exotic deciduous trees and conifers dominating early plantings. By the 1970's native species, mostly eucalypts, were planted. Today fewer species comprising an equal mix of native and exotics are used. Trees in the earlier plantings are now mature and given the harshness of the local climate many will come to the end of their ‘safe life’ in the early decades of this century. This provides new challenges for urban tree managers as to how to effect tree replacement that is aesthetically pleasing, ecologically sound and socially acceptable. To assist in this planning a tree data base and modeling system has been assembled. This system – Decision Information System for Managing Urban Trees or DISMUT – facilitates the development of forest-level management programs by allowing the projection of change and work requirements that the result from historical and current plantings over the entire urban forest. 相似文献
9.
Introduced tree species represent a substantial component of urban forests in cities all over the world. Yet there is controversy about the further use of introduced tree species. Many practice orientated publications,research papers and governmental websites in the fields of urban planning, urban forestry, and urban ecology argue for planting native species and avoiding introduced species. Such arguments for native-only species selection are also touted by environmental groups and the media. Consequently the debate has sometimes spiralled away from a sensible and rational platform where invasion risks and biodiversity loss are discussed, to a groundless and unreasonable argument where exotic species are generally considered incapable of providing ecosystem services. From a European perspective, we here aim to curate a set of necessary considerations for current and future discussions on native and non-native plant material in sustainable urban development. Using examples from Northern and Central Europe we illustrate that in some regions the catalogue of native tree species may be too limited to fulfil ecosystem services and resilience in harsh urban environments. A main message from our line of arguments is that we cannot afford to generally exclude non-native tree species from urban greening. If “native-only” approaches become incorporated in regional, national or international policy documents or legislation there is a risk that urban ecosystem resilience will be compromised, particularly in regions with extreme environmental conditions. Since both invasion risks and sizes of native species pools vary conspicuously at regional to continental scales we also argue to adapt urban policies on using non-native trees to regional contexts. 相似文献
10.
Research points to numerous benefits provided by urban street trees including qualitative and quantitative public health, economic, and environmental advantages for a city and its residents. As with other key aspects of city management that help develop municipal success, urban forestry requires foresight, commitment and planning that lead to effective policies and strategies. Good street tree management based on effective policies can maximise street tree benefits. Poorly conceived policies or the absence of effective policies can lead to the opposite result. A case study of the neighbouring cities of Loma Linda and Redlands, California illustrates this difference. The urban tree care and protection policies in these two cities have evolved differently. The differences may be attributable to contrasting municipal commitments to preservation and to best-practice management principles. Based on a comparative analysis of street tree policies of the two cities, it can be concluded that a local culture favouring tree protection and reflective guidelines and policies can result in proactive and successful management of an urban forest. Such policies also include provision for gathering data essential for strategic tree planting, care and removal. 相似文献
11.
Urban and community forestry is an increasingly integral component enhancing the well-being of urban places. Along with providing aesthetic benefits and other critical ecosystem services, urban forestry contributes to local and regional economies by supporting jobs and economic activities through various businesses and industries. In this study, we estimated the economic contribution of urban forestry to the regional economy in terms of several economic and business metrics including jobs, labor income, value-added, and tax collections. To this end, we developed an extensive scope of urban forest industries and activities incorporating all private, public, and non-profit businesses and organizations involved in urban forestry in the Northeastern and Midwest states. Results from the input-output modeling suggest that in 2018, urban forestry in the Northeastern and Midwest states directly contributed $17.6 billion in industry output and $13.5 billion in value-added by supporting about 258,550 full- and part-time jobs in various businesses and activities. Including direct, indirect, and induced effects, urban forestry in the region had a total contribution of $34.7 billion in industry output to the regional economy, employing more than 357,200 people with a payroll of about $16 billion. These numbers are crucial to highlight the economic significance of urban forestry businesses and agencies as well as to educate the public, economic development professionals, and legislators about the importance of urban and community forestry in the Northeastern and Midwest states. 相似文献
12.
Urban tree cover is inequitable in many American cities, with low-income and non-white neighborhoods typically having the least coverage. Some municipal and non-profit tree planting programs aim to address this inequity by targeting low-income neighborhoods; however, many programs face lack of participation or resistance from local residents. In this study, we aimed to uncover the economic, social, cultural, and physical barriers that community leaders face in planting trees and fostering engagement in a neighborhood with low tree canopy. In collaboration with an urban greening nonprofit in Philadelphia, Pennsylvania (US), twenty in-depth interviews were conducted with community leaders in a low canopy neighborhood, North Philadelphia. Half of these leaders were already involved with local tree planting programs, while the other half were not. Findings reveal that despite broad appreciation for trees and greenspaces, there are concerns about the risks and costs residents assume over the course of a tree’s life cycle, the threat of neighborhood development and gentrification associated with trees, limited plantable space, and limited time and capacity for community organizations. Additionally, these barriers to participation may be amplified among low-income and communities of color who face the legacies of historical tree disservices and municipal structural disinvestment. Addressing community concerns regarding the long-term care of trees beyond the initial tree planting would likely require further programmatic support. Overall, this research highlights the complexity of addressing inequities in tree canopy and the importance of integrating resident and community leader perspectives about disservices and management costs into tree planting initiatives. 相似文献
13.
The Fraxinus genus consists of ca. 65 deciduous, rarely evergreen trees found mainly throughout Europe, Asia and North America. Fraxinus species possess the aesthetic characteristics desired of urban trees (autumn colour, attractive bark and flowers); however, no scientifically based tolerance ranking exists for many genotypes within this genera. Aims of this study were to identify whether differences in drought tolerance exist within the Fraxinus genus and thereby provide information as to their usefulness for planting in urban landscapes where water stress poses a threat to transplant survival. At the cessation of a 2-week drought stress and subsequent recovery period, marked differences in drought tolerance among genotypes were distinguished based on net photosynthesis, leaf chlorophyll fluorescence and chlorophyll concentration. In addition, measurement of light absorbance, light trapping, electron transport and dissipation fluxes per leaf cross section of photosystem II at the cessation of the drought period provided an insight into mechanisms of drought damage and resilience among the genotypes tested. The results of this investigation indicate that F. excelsior ‘Aurea Pendula’, F. nigra Marsh., F. ornus L., F. angustifolia ‘Raywood’, F. excelsior L. and F. excelsior ‘Jaspidea’ should be considered for urban planting sites, where water supply is limited. Care should be taken when planting F. americana L., F. americana ‘Autumn Purple’ and F. velutina Torr., into urban environments as results indicated these species are sensitive to drought. 相似文献
14.
Urban forests produce ecosystem services that can benefit city dwellers, but are especially vulnerable to climate change stressors such as heat, drought, extreme winds and pests. Tree selection is an important decision point for managers wanting to transition to a more stable and resilient urban forest structure. This study describes a five-step process to identify and evaluate the performance of promising but infrequently used tree species. The approach is illustrated for the Central Valley of California, USA and has been implemented in the Inland Empire and Southern Coastal regions of California. Horticultural advisors nominated 134 taxon for consideration. A filtering process eliminated taxon that were relatively abundant in a compilation of 8 municipal tree inventories, then those with low adaptive capacity when scored on habitat suitability, physiology and biological interactions. In 2015, 144 trees were planted, with 2 trees of each of 12 species planted in 4 Sacramento parks and 4 replicates planted in the Davis, California reference site. This approach can serve as an international model for cities interested in climate adaptation through urban forestry. 相似文献
15.
Urban forest conditions are driven by a range of biophysical and social factors, including urban form, socioeconomic conditions, and municipal policy. However, relatively little attention has been paid to policies, particularly those aimed at private property. The purpose of this study was to identify the types of urban tree policies that exist in the Greater Toronto Area, begin to understand why those variations may occur, and determine if such variations lead to on-the-ground differences. To address these objectives, we conducted a survey to identify policies covering the planting and removal of privately owned trees, as well as publicly owned trees along roadways in 29 municipalities. The results of the survey were then compared to census and vegetation abundance data to determine the relationship between municipal characteristics, level of policy adoption, and on-the-ground differences. We found substantial variation in the type of policies in place, with regulations addressing tree protection on private property occurring only in larger municipalities. The existence of on-the-ground differences was less clear, possibly because of the relatively recent adoption of most policies. These results highlight the need to assist smaller municipalities in developing urban forestry policies and to monitor these policies’ influence over the long term to better understand their role in shaping the urban forest. 相似文献
16.
The effects of pre-bud-break application of 1.5% hydrogen cyanamide (3% Dormex) on the flowering and cropping of 12 apple cultivars were determined over the years 1988/89 to 1991/92 in tropical Zimbabwe, at a site with less than 300 h of winter chilling below 7.2 °C per year. Control trees, other than those of ‘Mutsu’ and ‘Goldjon’ which were indistinguishable from the treated trees, showed varying degrees of delayed flowering and low yield in comparison with the cyanamide-treated trees. The latter, irrespective of cultivar, attained full bloom within 4–5 weeks of the common date of treatment, so that blossoming of the different cultivars, as well as that of the different trees of each cultivar, was synchronized, and all cropped heavily in relation to tree size. Very satisfactory yields of ‘Mollies Delicious’, ‘Canvada’, ‘Drakenstein’, ‘Golden Delicious’, ‘NJ46’, ‘Marjorie Pye’, ‘Spartan’, ‘Starking’, ‘Granny Smith’ and ‘Ohinemuri’ were thus obtained by the use of cyanamide in an environment otherwise unsuitable for them, especially for the later cultivars on this list. 相似文献
17.
Tree ordinances can be an effective means of preserving urban forests in the face of development pressures. Despite this, they also have the potential to be divisive among the public - especially when applied to privately-owned land. In this study we surveyed 1716 Florida urban residents to understand how they value regulation and management of the urban forest. Specifically, we asked about: tree protection ordinances, incentive programs to manage or plant trees, justification for tree removal, and development. Most respondents supported tree protections, even when applied to trees on their own property or when they had the potential to limit development activities. Additionally, there was limited support for removing healthy trees for development. Respondents supported the use of funds for urban forestry efforts – particularly at the local or state level. 相似文献
18.
A systematic quantitative review of urban tree benefits,costs, and assessment methods across cities in different climatic zones 总被引：1，自引：0，他引：1
Urban trees can potentially mitigate environmental degradation accompanying rapid urbanisation via a range of tree benefits and services. But uncertainty exists about the extent of tree benefits and services because urban trees also impose costs (e.g. asthma) and may create hazards (e.g. windthrow). Few researchers have systematically assessed how urban tree benefits and costs vary across different cities, geographic scales and climates. This paper provides a quantitative review of 115 original urban tree studies, examining: (i) research locations, (ii) research methods, and (iii) assessment techniques for tree services and disservices. Researchers published findings in 33 journals from diverse disciplines including: forestry, land use planning, ecology, and economics. Research has been geographically concentrated (64% of studies were conducted in North America). Nearly all studies (91.3%) used quantitative research, and most studies (60%) employed natural science methods. Demonstrated tree benefits include: economic, social, health, visual and aesthetic benefits; identified ecosystem services include: carbon sequestration, air quality improvement, storm water attenuation, and energy conservation. Disservices include: maintenance costs, light attenuation, infrastructure damage and health problems, among others. Additional research is required to better inform public policy, including comparative assessment of tree services and disservices, and assessment of urban residents and land managers’ understanding of tree benefits and costs. 相似文献
19.
Urban trees provide a wide range of ecosystem services for city residents, with tall, mature trees with wide crowns generally regarded as preferable. The tree biomass which is responsible for shading, pollution removal, rain runoff retention etc. gets periodically reduced by the municipal tree management practice of pruning. This is a necessary activity, which reduces the risk of infrastructure damage and falling branches, but many estimates of ecosystem service provision in cities do not consider its impact explicitly. Tree mortality is also higher in cities, preventing trees from attaining and remaining at large sizes. This study used extensive field measurements of tree structure to estimate the impact of pruning on 8 tree species in two Italian cities: Taranto and Florence. Crown widths were reduced by 1.6 m on average, however there is large variation between species variation with branches more often being removed for thinning crowns resulting in larger gap fractions, which increased by 15% on average. No significant differences were observed for crown widths or gap fraction between trees pruned 3 and 4 years previously, suggesting that tree crowns structurally recover from pruning after 3 years. A deterministic model revealed that current urban forest pruning rates (every 6 years) and mortality (1%) may create a situation in which a city dominated by the species studied benefits from 93.5% of the maximum ecosystem services possible. This work will allow more nuanced estimates of urban forest services to be calculated. 相似文献
20.
Based on re-measurements (1999 and 2001) of randomly-distributed permanent plots within the city boundaries of Baltimore, Maryland, trees are estimated to have an annual mortality rate of 6.6% with an overall annual net change in the number of live trees of –4.2%. Tree mortality rates were significantly different based on tree size, condition, species, and land use. Morus alba, Ailanthus altissima, and trees in small diameter classes, poor condition, or in transportation or commercial – industrial land uses exhibited relatively high mortality rates. Trees in medium- to low-density residential areas exhibited low mortality rates. The high mortality rate for A. altissima is an artifact of this species distribution among land use types (24% were in the transportation land use). Based on a new tree population projection model that incorporates Baltimore's existing tree population and annual mortality estimates, along with estimates of annual tree growth, Baltimore's urban forest is projected to decline in both number of trees and canopy area over the next century. Factors affecting urban tree mortality are discussed. 相似文献