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Temporal and spatial variation in garden and street trees in six eastern Australian cities
Abstract
Trees are an economically, socially and culturally important component of cities, yet, in single city studies, appear to be less dense in areas of low income and educational status than in areas of high income and education status. We found that this pattern occurred in six Australian cities over the period 1961ā2006, with conditions in 1961 predicting those in 2006. Tree presence in gardens conformed similarly to predictors between cities, but the presence of street trees and the type of both street or garden trees did not. Our data suggest that it would be possible to plan to double the number of street trees in Australian cities in present circumstances, but that significant increases in garden tree numbers would depend on increasing the income and higher education attainment of lower socioeconomic groups.
... The uneven distribution of urban trees and the complexity of ensuring environmental equity raise questions about the physical, ecological and socio-economic correlates as well as the underlying mechanisms associated with urban tree distributions. The distribution of street trees can be city-specific since public policies concerning this issue are determined on the basis of site-specific factors such as climate, geographic conditions, history and preferences (Kirkpatrick, Daniels, & Davison, 2011). While there is a growing body of literature addressing urban tree cover at the household or parcel scale of analysis, many of these studies focus on residential tree cover rather than on street trees or street tree cover (e.g. ...
... Studies addressing correlates of street trees focus mostly on socio-economic factors that have been reported at larger geographic scales, such as suburbs in Australia, census block groups in the United States or dissemination areas in Canada (Kirkpatrick et al., 2011;Landry & Chakraborty, 2009;Pham, Apparicio, Landry, SĆ©guin, & Gagnon, 2013), with only one study (from Bangalore, India) looking at street characteristics (Nagendra & Gopal, 2010). The three Western studies were conducted in very different cities in terms of climate conditions and population density and with different sets of correlates. ...
... The three Western studies were conducted in very different cities in terms of climate conditions and population density and with different sets of correlates. Kirkpatrick et al. (2011) used two income variables in suburbs of six Australian cities. Landry and Chakraborty (2009), examining street trees from an equity angle, used socio-demographic variables and one variable related to the built environment (median housing age) in Tampa, Florida (United States). Pham et al. (2013) looked at socio-demographic variables and two proxies of the built environment (population density and construction age of parcels) in MontrƩal, Canada. ...
... Associated with increased research on the roles, benefits and functions of urban vegetation, including trees, is an increasing focus on the factors influencing urban tree distribution. However, much of this focus has been on a narrow selection of influencing factors, including the impact of social and temporal factors such as race, income, education, and historic socio-economic characteristics and land-use (Landry & Chakroborty 2009;Kabisch & Haase 2014;Santamouris & Asakopoulos 2001;Heynen et al. 2006;Luck et al. 2009;Heynen & Lindsey 2003;Shanahan et al. 2014;Kirkpatrick et al. 2007;Kendal et al. 2012;Kirkpatrick et al. 2011;Krafft & Fryd 2016). Most studies have focused on trees within the public domain (Landry & Chakraborty 2009;Kirkpatrick et al. 2009;Kirkpatrick et al. 2011). ...
... However, much of this focus has been on a narrow selection of influencing factors, including the impact of social and temporal factors such as race, income, education, and historic socio-economic characteristics and land-use (Landry & Chakroborty 2009;Kabisch & Haase 2014;Santamouris & Asakopoulos 2001;Heynen et al. 2006;Luck et al. 2009;Heynen & Lindsey 2003;Shanahan et al. 2014;Kirkpatrick et al. 2007;Kendal et al. 2012;Kirkpatrick et al. 2011;Krafft & Fryd 2016). Most studies have focused on trees within the public domain (Landry & Chakraborty 2009;Kirkpatrick et al. 2009;Kirkpatrick et al. 2011). Where the relationship between urban density and canopy cover has been studied, the relationship is usually observed at a neighbourhood or city scale, concluding that an increase in density results in decreased canopy cover due to the decreased area available for trees (Kabisch & Hasse 2014;Kendal et al. 2012;Troy et al. 2007;Rodriguez et al. 2004;Kirkpatrick et al. 2007;Cook et al. 2015). ...
... This study's focus on urban trees in the private realm is important as private land contributes significantly to urban tree canopies (Kirkpatrick et al. 2009;Kirkpatrick et al. 2011;Cook et al. 2015). Furthermore, current Australian planning regulations have limited influence on private gardens (Kirkpatrick et al. 2009;Kirkpatrick et al. 2011), with owners' personal preferences, and social variables the dominant influences on gardening practices (Kendal et al. 2012;Shanahan et al. 2014). ...
Urban trees provide substantial ecosystem services, and trees on private land are a sizeable segment of overall urban tree cover. Trees provide shade, cooling and habitat, and contribute to aesthetic values, sense of place, and urban dwellers' mental and physical wellbeing. With increasing size and density of cities, tree cover decreases, as buildings replace private open spaces. As a result, there is intensifying focus on establishment and maintenance of trees in public spaces, through street tree establishment, and in public open spaces. There has been less research on tree cover in private open space in areas of increasing residential density. This research focuses on the influence of development density on urban trees on private residential land. Specifically, we analysed the relationship between dwelling density and the proportion of available land that is used for trees. Available land within residential properties may be used for a number of different purposes, including tree cover, garden beds, paved surfaces and so on. Our analysis utilised data on recent multi-unit residential development and GIS-based analysis of aerial photos of inner city areas in Melbourne, Australia. We found that with an increase in development density, tree cover increases proportionally compared with other private open space uses. Changes to soft landscaping cover had greater impact than development density on the proportion of tree cover in private open space. Our research can be utilised by policy-makers seeking to maximise urban tree cover. Further research could examine the social and policy influences on hard and soft landscaping practices.
... Trees are an important element of the city and suburbs, benefiting and inconveniencing other urbanites in manifold ways [1][2][3][4][5]. Therefore, it is not surprising that there has been a growing literature documenting temporal change in urban tree density and cover [6][7][8][9][10][11] and testing hypotheses on the causes of change [12][13][14][15][16][17][18]. multi-thresholds followed by multi-resolution segmentation to segment the surface model into finer objects. ...
... Trees in domestic gardens have been shown to be associated with high levels of household incomes [14][15][16][17][18]58,59], high levels of education [15][16][17]58,60] and large block size [16]. Motives for planting and removing trees have proven to be highly varied, as have preferences for particular types of trees, suggesting that changes of garden ownership may be a major cause of tree changes in suburbia [61,62]. ...
... Trees in domestic gardens have been shown to be associated with high levels of household incomes [14][15][16][17][18]58,59], high levels of education [15][16][17]58,60] and large block size [16]. Motives for planting and removing trees have proven to be highly varied, as have preferences for particular types of trees, suggesting that changes of garden ownership may be a major cause of tree changes in suburbia [61,62]. ...
Urban trees provide social, economic, environmental and ecosystem services benefits that improve the liveability of cities and contribute to individual and community wellbeing. There is thus a need for effective mapping, monitoring and maintenance of urban trees. Remote sensing technologies can effectively map and monitor urban tree coverage and changes over time as an efficient and low-cost alternative to field-based measurements, which are time consuming and costly. Automatic extraction of urban land cover features with high accuracy is a challenging task, and it demands object based artificial intelligence workflows for efficiency and thematic accuracy. The aim of this research is to effectively map urban tree cover changes and model the relationship of such changes with socioeconomic variables. The object-based convolutional neural network (CNN) method is illustrated by mapping urban tree cover changes between 2005 and 2015/16 using satellite, Google Earth imageries and Light Detection and Ranging (LiDAR) datasets. The training sample for CNN model was generated by Object Based Image Analysis (OBIA) using thresholds in a Canopy Height Model (CHM) and the Normalised Difference Vegetation Index (NDVI). The tree heatmap produced from the CNN model was further refined using OBIA. Tree cover loss, gain and persistence was extracted, and multiple regression analysis was applied to model the relationship with socioeconomic variables. The overall accuracy and kappa coefficient of tree cover extraction was 96% and 0.77 for 2005 images and 98% and 0.93 for 2015/16 images, indicating that the object-based CNN technique can be effectively implemented for urban tree coverage mapping and monitoring. There was a decline in tree coverage in all suburbs. Mean parcel size and median household income were significantly related to tree cover loss (R 2 = 58.5%). Tree cover gain and persistence had positive relationship with tertiary education, parcel size and ownership change (gain: R 2 = 67.8% and persistence: R 2 = 75.3%). The research findings demonstrated that remote sensing data with intelligent processing can contribute to the development of policy input for management of tree coverage in cities.
... The luxury effect has since been found in respect to plant diversity in North America, Burundi, China and Australia [4][5][6][7][8][9]. Other studies have used the concept of the luxury effect to describe the effect of affluence, not on plant diversity per se, but on the greenness of neighbourhoods in cities, measured using remote sensing tools focused on tree canopy or ground vegetation cover [10][11][12][13][14][15]. ...
... As with socioeconomics, techniques for evaluating 'biodiversity' also vary. Many use a diversity, or richness [3][4][5][6][7][8][17][18][19][20]23,26], whether measured at a single square metre [30] or whole city blocks. Other measurements of diversity that require abundance data, such as community composition, diversity indices, density or evenness are less frequently used [17,20,31]. ...
... (e) Environmental context and regional differences Vegetation luxury effect patterns have been found around the world [3,6,10,11,14,15], yet the strength of the luxury effect is, in part, contingent on the background ecosystem in which a city is built. For example, although urbanization has a tendency to decouple vegetation from precipitation compared to neighbouring wildland areas [15] a particularly strong relationship between affluence and biodiversity has been found in waterlimited regions [14,15]. ...
The ecological dynamics of cities are influenced not only by geophysical and biological factors, but also by aspects of human society. In cities around the world, a pattern of higher biodiversity in affluent neighbourhoods has been termed 'the luxury effect'. The luxury effect has been found globally regarding plant diversity and canopy or vegetative cover. Fewer studies have considered the luxury effect and animals, yet it has been recognized in the distributions of birds, bats, lizards and indoor arthropods. Higher socioeconomic status correlates with higher biodiversity resulting from many interacting factors-the creation and maintenance of green space on private and public lands, the tendency of both humans and other species to favour environmentally desirable areas, while avoiding environmental burdens, as well as enduring legacy effects. The luxury effect is amplified in arid cities and as neighbourhoods age, and reduced in tropical areas. Where the luxury effect exists, benefits of urban biodiversity are unequally distributed, particularly in low-income neighbourhoods with higher minority populations. The equal distribution of biodiversity in cities, and thus the elimination of the luxury effect, is a worthy societal goal.
... Interest in the relationship between canopy cover and socio-economic difference in and through urban space has flourished in North America (Heynen 2003;Heynen, Perkins and Roy 2006) and Australia (Kendal et al. 2012;Kirkpatrick et al. 2011). Researchers working in North American especially have explored how and why vulnerable populations in particular urban spaces disproportionately lack tree and green space provision. ...
... Returning to tree canopy specifically and the Australian context, similar dynamics are observed, though the emphasis has largely been on linking trees to one or more socio-economic variables, rather than explicitly addressing questions of environmental injustice. In their comprehensive study of six eastern Australian cities at the scale of city suburbs within Local Government Areas, Kirkpatrick, Daniels and Davison (2011) found that: ...
Trees are known for their positive impacts in cities including: the provision of shade, reducing heat island effects, improving amenity, reducing social vulnerability, processing carbon and improving health outcomes. Perhaps unsurprisingly, greening policies at the local and state level have proliferated. Despite these initiatives, tree cover remains stubbornly uneven. A cursory analysis of vulnerability and tree-cover by location shows that those who are most vulnerable to extreme heat events (Loughnan et al 2013) often live in those parts of cities that are most poorly shaded (ISF, 2014). Drawing on a new set of 50 online questionnaire and face-to-face interviews with local council officers in Melbourne conducted in 2014, the aim of this paper is to identify the actors and processes shaping the provision of the urban tree canopy. The results emphasise: i) the wide range of public and private organisations that, in collaboration, provide and maintain tree-cover; ii) the key role of residents within these governance frameworks; iii) the impact of urban development histories on opportunities and limits for urban greening. Theoretically, the paper advances relational models of urban governance in the context of resilient cities showing the urban canopy is the product of diverse actors and agents operating across hybrid and fluid public and private spaces (McGuirk 2012). Recognising this, the paper highlights opportunities for engagement with residents in greening initiatives; and a new integration of ecological and social data through which greening strategies can target those of greatest heat vulnerability.
... The trees are being mapped with accuracy through advance tools in some urban areas (TanhuanpƤƤ et al., 2014;Seiferling et al., 2017). In recent years, different attributes of street tree community have been investigated in many urban landscapes across the globe for the enhancement of their sustainability in the densely populated human settlements (Frank et al., 2006;McKinney, 2006McKinney, , 2008Deliang, 2009;Nagendra and Gopal, 2010;Kirkpatrick et al., 2011;Ressler and Kilmer, 2012;Kuruneri-Chitepo and Shackleton, 2011;Yang et al., 2012;Deb et al., 2013;Choi and Kim, 2014;Cowett and Bassuk, 2014;McPherson et al., 2016;Nero et al., 2017;Gwedla and Shackleton, 2017). The studies on the street trees revealed significant variation in their attributes within the streetscapes of many urban areas, which may be because of the socio-economic and educational status of different areas (Hope et al., 2003;Kirkpatrick et al., 2011;Gwedla and Shackleton, 2017), the cultural background, preference or attitude of urban residents for different sizes, shapes and growth rates of street trees (Williams, 2002;Todorova et al., 2004;Schhroeder et al., 2006) or the replacement of street trees due to pests, diseases or infections (Heimlich et al., 2008). ...
... In recent years, different attributes of street tree community have been investigated in many urban landscapes across the globe for the enhancement of their sustainability in the densely populated human settlements (Frank et al., 2006;McKinney, 2006McKinney, , 2008Deliang, 2009;Nagendra and Gopal, 2010;Kirkpatrick et al., 2011;Ressler and Kilmer, 2012;Kuruneri-Chitepo and Shackleton, 2011;Yang et al., 2012;Deb et al., 2013;Choi and Kim, 2014;Cowett and Bassuk, 2014;McPherson et al., 2016;Nero et al., 2017;Gwedla and Shackleton, 2017). The studies on the street trees revealed significant variation in their attributes within the streetscapes of many urban areas, which may be because of the socio-economic and educational status of different areas (Hope et al., 2003;Kirkpatrick et al., 2011;Gwedla and Shackleton, 2017), the cultural background, preference or attitude of urban residents for different sizes, shapes and growth rates of street trees (Williams, 2002;Todorova et al., 2004;Schhroeder et al., 2006) or the replacement of street trees due to pests, diseases or infections (Heimlich et al., 2008). Pham et al. (2017) investigated the effects of street characteristics, social stratification and lifestyle for the variations of street tree cover in MontrƩal, Canada. ...
Abstract
Despite being one of the largest and fastest growing cities of the world, little is known about the urban forest of Karachi. The city consists of eighteen towns. Each town has different socioeconomic status. Therefore, the present study investigates 1) the patterns and differences in the diversity and density of street tree communities across the towns of different socio-economic status, 2) the patterns and differences in the diversity and density of the communities of different road widths, 3) the factors that cause variation in different attributes of the community. The study revealed significant variation in the diversity and density of the tree community of different towns and road categories. The socioeconomic status of towns and different road categories demonstrated statistically significant influence in determining their tree density and species diversity. Statistically significant correlation was found between socioeconomic status and tree density per thousand inhabitants of towns. The study divulges recurring planting of one or few species that decrease the species diversity in many towns and streets. Conocarpus erectus revealed strong dominance on wide and medium width roads while it demonstrated co-dominance with Azadirachta indica on narrow roads. Overall, 62 species (30 native and 32 exotic) were recorded, which were very unevenly distributed in the streetscape of the city. The study also discusses the socioeconomic factors and role of civic agencies in planting trees.
... Urban parks and woodlands are more often located in wealthier neighbourhoods (Poudyal et al., 2009) and require leisure time to enjoy as they are often located some distance from urban residents' homes (Harnik, 2010). The size and abundance of trees on private property are often higher in high-income neighbourhoods (Kirkpatrick et al., 2011) and lower levels of canopy cover across all land ownership types are more often associated with lower-income neighbourhoods (Landry and Chakraborty, 2009;Nesbitt and Meitner, 2016;Schwarz et al., 2015). In some cases, socioeconomically disadvantaged urban residents are less likely to engage in urban vegetation stewardship activities, to participate in urban forestry decision making, and to have control over urban vegetation resources (Buijs et al., 2016;Heynen, 2003). ...
... Despite the clear positive influence of urban vegetation in the lives of urban residents, the distribution of urban vegetation appears to be uneven in many cities (Heynen and Lindsey, 2003;Landry and Chakraborty, 2009;McConnachie and Shackleton, 2010;Nesbitt and Meitner, 2016;Ogneva-Himmelberger et al., 2009). Research has shown that public parks are more often located in higher income neighbourhoods (Poudyal et al., 2009), trees on private property are often larger and more numerous in wealthier neighbourhoods (Kirkpatrick et al., 2011), and lower levels of canopy cover are more often found in lower-income neighbourhoods (Landry and Chakraborty, 2009;Schwarz et al., 2015). ...
Urban vegetation provides a suite of ecosystem services to urban residents, from regulating microclimate to supporting good physical health. As more and more people make cities their home, urban vegetation is becoming a key part of urban residentsā well-being. Urban green equity is a central aspect of the distribution of and governance over urban vegetation and its associated ecosystem services. While issues of equity in urban forestry are of clear importance in a just society, it is unclear how the concept should be defined and analyzed. To begin to address this gap, this dissertation 1) examines the theoretical dimensions of urban green equity from multiple perspectives, 2) explores how urban forestry practitioners understand and use the concept of urban green equity in three case-study cities in the United States (US), and 3) conducts a spatial analysis of distributional green equity across 10 urbanized areas in the US. The research found 1) that there are multiple, related dimensions of urban green equity centred around two principle dimensions: distribution of urban vegetation and recognition of stakeholders in urban vegetation decision making, 2) that urban forestry practitioners collectively have a nuanced and complex understanding of urban green equity and tend to focus on distributional equity in their definitions and use of the concept, and 3) that distributional green inequity exists across multiple urbanized areas in the US, education and income are the factors most strongly predictive of the spatial distribution of urban vegetation, and public parks tend to be more equitably distributed than mixed and woody vegetation in cities. It is my hope that these results, and the methodological and conceptual approaches and frameworks provided by this research will be used to advance the rigorous study of urban green equity and improve urban green equity in practice in cities around the world.
... Spatial and social contagion (where residents' social interactions drive similarity in garden style) are well documented in residential gardening in the UK, USA and Australia (e.g. Askew and McGuirk, 2004;Goddard et al., 2013: Kirkpatrick et al., 2007Kirkpatrick et al., 2011;Nassauer et al., 2009). Spatial contagion may also influence verge garden distribution, i.e. verge gardening may tend to encourage further verge gardening in neighbouring properties. ...
... The uneven spread of greenspace in a city in relation to income has been well researched (Jenerette et al., 2011;Kirkpatrick et al., 2011;Kendal et al., 2012). We found that verge understorey gardening was more likely in more advantaged suburbs than disadvantaged suburbs. ...
Verge gardening is a citizen-led form of public urban greening where residents plant and maintain understorey and trees in the road easement, and it has the potential to significantly increase the diversity and complexity of street greenery which is, most commonly, mown grass and monocultures of street trees. In Melbourne, Australia, two forms of verge gardening ā understorey planted by residents and street trees planted by residentsā were investigated. The distribution of verge gardens was tested for correlation with a range of urban form and social factors that included the proportion of garden in residential parcels, the proportion of the street set aside as road verge, age of street development, the presence of footpaths, tree cut-outs (tree pits) and social disadvantage. By better understanding the factors associated with verge gardening, we hope planners, urban designers and land managers will be able to better incorporate verge gardening into urban greening strategies and so maximise the biodiversity, ecosystem function and human amenity benefits associated with this significant public activity. We found that verge gardening was common, occurring in almost a quarter (22.1%) of verges and was strongly associated with verges without footpaths, tree cut-outs rather than continuous verges, and verges on local roads rather than collector roads. Neighbourhoods with proportionally more garden had more verge gardening. With the exception of the oldest streets in our study, streets that were newer had more verge gardening than those that were older. The presence of street trees planted by local government was associated with less verge gardening. Verge gardening was less common in neighbourhoods with greater social disadvantage, and spatial contagion increased the likelihood of neighbours having verge gardens. Local government can facilitate verge gardening through engagement, education, adopting alternative street types, using tree cut-outs to better strategic advantage, and targeting areas of social disadvantage.
... The south-eastern region of Melbourne includes several older, established suburbs as well as suburbs that have been recently developed as Melbourne's population expands. As seen throughout Australia, the majority of housing in both the older and newer suburbs consists of low-density detached houses with both front and rear gardens (Kellett, 2011;Kirkpatrick, Daniels, & Davison, 2011). Gardens in south-east Melbourne's older suburbs are often larger and more likely to contain trees, while those in newer suburbs are generally smaller, less established and include shrubs and groundcovers rather than larger plant forms (Ghosh & Head, 2009). ...
... Quantification of vegetation cover was achieved by placing a 10 Ć 10 grid over each landscape image and counting the number of grid cells containing lawn, shrubs and flowers, and trees (Tveit, 2009). Trees were defined as taller, canopy forming plants typically growing greater than five metres tall; mown lawn; and shrubs and flowers were considered to be any plant that was not lawn or a tree (Kirkpatrick et al., 2011). ...
Landscape preferences shape decision-making and drive the ecological outcomes of urban landscapes. We investigate how peopleās landscape preferences are shaped by the green space context (public park vs private residential garden landscapes) and by physical features such as vegetation complexity. A postal questionnaire was sent to households near seven urban parks in Melbourne, Australia. Results showed that landscapes were grouped into four categories based on patterns of preference response. Landscapes with moderate vegetation complexity were placed in separate categories distinguished by green space context (parks vs gardens), while very simple and very complex landscapes were placed in different categories irrespective of green space context. Surprisingly, dense vegetation was highly preferred by respondents. As areas of dense vegetation also provide complex habitats for wildlife, this highlights the possibility of developing policies and designing landscapes that can benefit both people and nature.
... Spatial and social contagion (where residents' social interactions drive similarity in garden style) are well documented in residential gardening in the UK, USA and Australia (e.g. Askew and McGuirk, 2004;Goddard et al., 2013: Kirkpatrick et al., 2007Kirkpatrick et al., 2011;Nassauer et al., 2009). Spatial contagion may also influence verge garden distribution, i.e. verge gardening may tend to encourage further verge gardening in neighbouring properties. ...
... The uneven spread of greenspace in a city in relation to income has been well researched (Jenerette et al., 2011;Kirkpatrick et al., 2011;Kendal et al., 2012). We found that verge understorey gardening was more likely in more advantaged suburbs than disadvantaged suburbs. ...
Verge gardening is a citizen-led form of public urban greening where residents plant and maintain understorey and trees in the road easement, and it has the potential to significantly increase the diversity and complexity of street greenery which is, most commonly, mown grass and monocultures of street trees. In Melbourne, Australia, two forms of verge gardening-understorey planted by residents and street trees planted by residents, were investigated. The distribution of verge gardens was tested for correlation with a range of urban form and social factors that included the proportion of garden in residential parcels, the proportion of the street set aside as road verge, age of street development, the presence of footpaths, tree cutouts (tree pits) and social disadvantage. By better understanding the factors associated with verge gardening, we hope planners, urban designers and land managers will be able to better incorporate verge gardening into urban greening strategies and so maximise the biodiversity , ecosystem function and human amenity benefits associated with this significant public activity. We found that verge gardening was common, occurring in almost a quarter (22.1%) of verges and was strongly associated with verges without footpaths, tree cutouts rather than continuous verges, and verges on local roads rather than collector roads. Neighbourhoods with proportionally more garden had more verge gardening. With the exception of the oldest streets in our study, streets that were newer had more verge gardening than those that were older. The presence of street trees planted by local government was associated with less verge gardening. Verge gardening was less common in neighbourhoods with greater social disadvantage, and spatial contagion increased the likelihood of neighbours having verge gardens. Local government can facilitate verge gardening through engagement , education, adopting alternative street types, using tree cutouts to better strategic advantage, and targeting areas of social disadvantage.
... In Phoenix, AZ, the negative correlation between normalised difference vegetation index (NDVI) and Gini coefficient reflected aggravation in income disparity throughout the late 20th century (Jenerette et al., 2011). In Brisbane, Australia, income and education attainment were positively correlated with tree number in private garden (Kirkpatrick et al., 2011). Other variables examined in tandem with urban greenery included age (Maas et al., 2009), gender imbalance (Cole et al., 2017;Evans et al., 2012), education attainment (Grove et al., 2006), disposable income (Pedlowski et al., 2002), ethnicity (Landry and Chakraborty, 2009), and usual language (Cole et al., 2017;Conway et al., 2011). ...
... Besides adequate consideration of socio-economic and ecological variables, suitable research methods would be necessary for generating tenable results and useful implications. The scale of the sampling unit varied notably, including suburb (Gwedla and Shackleton, 2017), urban centre and district (Astell-Burt et al., 2014), neighbourhood (Pedlowski et al., 2002), street (Nagendra and Gopal, 2010), household (Kimpton, 2017) and backyard (Kirkpatrick et al., 2011). Increasing the size of the sampling units would drive their socio-economic traits towards the aggregate population of the entire study area, and tone down the disproportionality in urban-tree provision. ...
Socio-economically underprivileged urban communities might suffer from restricted access to urban forests. Environmental injustice research on urban greenery in Asian cities is lacking. Public housing estates in Hong Kong, accommodating low-income households and over half of the 7.45 million population, were investigated for injustice in tree provision. Two clustering schemes used socio-economic and ecological characteristics to classify 93 estates. Factor analysis of 14 socio-economic variables identified four factors related to deprivation, namely ageing population, overcrowding, working poor with high academic qualifications, and marginalised language minorities. Principal component analysis of six ecological indices returned two components related to tree density and diversity. Estates with ageing population and more language minorities had the least urban tree provision indicated by low tree density. However, estates beset by overcrowding and working poor with high academic qualifications had the highest tree diversity indicated by the highest species evenness. Estates with the lowest language minorities had the densest but the least diverse tree stands. An alternative clustering scheme delineating ecological clusters substantiated the observed urban-tree patterns with respect to socio-economic characteristics. Estates with higher tree density and diversity had higher population density indicating overcrowding. Estates with lower tree density and diversity had more ageing population language minorities. The results highlighted the need to modify tree provision in response to changing estate demographics. From the research findings, five strategies were developed to adjust the amount and composition of the estate tree stocks to achieve greater social inclusion.
... Other studies have shown that attitudes and actions towards urban trees can be affected by socio-economic characteristics. For example, residents with relatively high income and education levels are more likely to support urban forest policies and engage in urban forest management (Conway & Bang, 2014;Kirkpatrick, Daniels, & Davison, 2011;Zhang, Hussain, Deng, & Letson, 2007;Zhang & Zheng, 2011). Ethno-cultural diversity has also been shown to be an important mechanism of varied resident attitudes towards trees (Fraser & Kenney, 2000), and thus it too can affect tree planting and removal (OrdĆ³Ć±ez, 2017). ...
... Ethno-cultural diversity has also been shown to be an important mechanism of varied resident attitudes towards trees (Fraser & Kenney, 2000), and thus it too can affect tree planting and removal (OrdĆ³Ć±ez, 2017). Other socio-economic variables, such as house tenure, age, and employment, can also influence treerelated decisions in the context of urban development (Kirkpatrick et al., 2011). ...
As a global phenomenon, redevelopment in cities influences urban forest dynamics. This study explores the relationship between resident attitudes and tree removal, retention, and planting on redeveloped versus non-redeveloped private properties in Christchurch, New Zealand. Residents were surveyed via questionnaire between October 2016 and January 2017. The results indicate that residents from redeveloped properties were more likely to engage in tree removal and planting, while residents from non-redeveloped properties were more likely to retain existing trees. Principle component analysis identified reasons for tree removal, retention, and planting. The main reasons for tree removal were related to tree conflict with redevelopment, poor tree health, and residentsā concerns about ecosystem disservices (e.g. shade, litter). Residents from redeveloped properties were more likely to remove trees to achieve development outcomes, while residents from non-redeveloped properties were more likely to remove trees because they perceived the tree to be in poor health. Ecosystem services were commonly identified by respondents as reasons for tree retention and tree planting. While numerous ecosystem services (e.g. habitat provision, air quality improvement, provision of privacy) were identified by both groups of respondents, residents on redeveloped properties were more likely to plant trees due to their potential to improve property aesthetics. Finally, residents suggested that the reasons for retaining trees on their properties were related to the high cost of removal and the existence of government regulation for tree protection. These findings support the use of legislation, bylaws, and financial disincentives to limit tree removal during property redevelopment.
... In addition to population density and housing age, prior research has also quantified how other socioeconomic factors such as income and lifestyle might shape human behavior and urban development, which in turn, may affect urban C storage in a variety of ways. Socioeconomic status, such as income, has predicted the richness, abundance, and greenness of vegetation based on the idea of the "luxury effect" (sensu Hope et al., 2003), in which higher income households make greater investments in landscaping their private yards and public spaces, resulting in greater plant diversity and density (Hope et al., 2003, Kirkpatrick, Daniels, & Davison, 2011, Luck, Smallbone, & O'Brien, 2009, Jenerette et al., 2013, Leong, Dunn, & Trautwein, 2018. Social stratification theory posits that an empowered citizenry has greater influence on investment in public spaces, leading to increased numbers of street trees and canopy cover . ...
... In addition to changing in tandem with housing age, we also found that above-ground C stocks varied as a function of median income, which is a proxy for social stratification. While previous research has not explicitly examined the relationships among socioeconomic status and biomass C storage (but see Raciti et al., 2014), prior work has demonstrated similar linkages with vegetation cover, greenness, and diversity (Kirkpatrick et al., 2011, Luck et al., 2009, Jenerette et al., 2013Schwarz et al., 2015;Leong et al., 2018). Our results extend this phenomenon of the "luxury effect" (sensu Hope et al., 2003) to include increases in biomass C storage that accompany higher median incomes. ...
Research on patterns of below-ground carbon (C) storage in urban lawns has focused on biogeochemical mechanisms, with human activities playing an important but somewhat secondary role. By contrast, studies of above-ground vegetation in urban areas have emphasized socioeconomic factors that influence greenness, abundance , and diversity, without explicitly considering biogeochemical mechanisms. Here we examine how both biogeochemical and socioeconomic factors influence patterns of C storage in urban yards both above-and below-ground. We combined measurements of above-and below-ground C stocks in 36 lawns located in the small city (< 200,000 residents) of Manchester, New Hampshire, USA with a suite of indicators such as housing age, population density, median income, home value, and residence duration that we obtained from public assessment databases, the decennial census, and the American Community Survey. We found that for this small city, housing age was the only variable that was significant and positively correlated with soil C stocks. Median income, median resident age, and percent married couples were significant and positively related with above-ground biomass C, with housing age playing a secondary role. The disparity that we observed in how biogeochemical and socioeconomic factors shape the distribution of C stocks in urban yards highlights the need for management approaches tailored to sequestering C in above-versus below-ground pools. Understanding the C dynamics of small cities is critical to ensuring that urban areas of all sizes can enhance urban C storage and minimize urban C loss.
... One study in Montreal, Canada also reported that there exists income-based inequality as street tree cover is higher in affluent neighborhoods than in low-income neighborhoods (Pham et al., 2017). Based on case studies in six Australian cities, Kirkpatrick et al. (2011) found that local areas that have higher percentages of high income and education levels are likely to have more street trees. Most studies employ tree canopy cover to measure street tree inequalities (Lin et al., 2021). ...
... This study focused exclusively on street tree inequality and contributes to the existing literature in several ways. First, most street tree studies focus on specific socioeconomic and demographic aspects of inequalities, with income-based inequality being the most examined (Kirkpatrick et al., 2011;Neckerman et al., 2009). This study examined 11 variables that cover diverse aspects of residents' characteristics, including income, race, education, age, and lifestyle. ...
Most street tree inequality studies focus on examining tree abundance at single time point, while overlooking inequality dynamics measured based on a complete set of tree measures. Whether the severities of street tree inequalities vary with different tree structure measures, whether street tree inequalities are diminishing or growing over time, and how the inequality dynamics are affected by tree-planting programs remain largely unexplored. To fill these gaps, this study applied binned regression and cluster analyses to street tree census data of 1995ā2015 in New York City. We investigated different structural measures of street tree inequalities pertaining to various aggregations of people, compared street tree inequalities over time, and revealed the inequity remediation role of the MillionTreesNYC initiative. We found that the underprivileged populations, characterized by higher percentages of the poor, racial minorities, young people, and less-educated people, are more likely to have lower tree abundance, less desired tree structure, poorer tree health condition, and more sidewalk damages. When disaggregating inequalities across various aggregations of people, income-based and education-based inequalities were the most severe, but the inequalities diminished over time. The race-based and age-based inequalities show mixed results that disfavor Hispanics, Blacks, and young people. The equity outcome of the MillionTreesNYC initiative is not ideal as the inequalities decrease when measured using tree count and species diversity, whereas they increase when measured using tree health and average diameter at breast height. The findings have important implications for more effective decision-making to balance resources between planting trees and protecting existing trees, and between increasing tree abundance and improving tree structure.
... Although urban greenery has important, positive impacts on various aspects of urban quality of life, the distribution of urban greenery appears to be inequitable in many cities around the world [19][20][21][22][23][24]. Urban green spaces are most often located in wealthier neighbourhoods [6] and trees on private property are often larger and more abundant in high income neighbourhoods [25]. The canopy cover of public street trees can also vary widely within cities, and lower levels of canopy cover are more often found in lower-income neighbourhoods [20,23]. ...
... While there is strong evidence of the environmental, psychological, physical health, and economic benefits of trees [2][3][4][5][6][7][8], and evidence of aesthetic preference for urban greenery [48], it is important to note that some urban residents may prefer not to live near urban greenery. Preferences for urban greenery appear to be influenced by culture [55][56][57] and may also be influenced by socioeconomic background [25]. Low levels of urban greenery and large distances to urban parks would not be considered to be problematic by such residents. ...
Do urban residents experience societal benefits derived from urban forests equitably? We conducted a broad-scale spatial analysis of the relationship between urban greenery and socioeconomic factors in the Portland metropolitan area. The Normalized Difference Vegetation Index was derived from National Agriculture Imagery Program images to map urban vegetation cover, and Outdoor Recreation and Conservation Area data were used to identify green spaces. These measures of urban greenery were correlated with census data to identify socioeconomic factors associated with high levels of green inequity. Population density, house age, income, and race were strongly correlated with vegetation cover. However, the distribution of green spaces showed a much weaker relationship with socioeconomic factors. These results highlight the importance of different measures of access to urban greenery and suggest potential solutions to the problem of urban green inequity. Cities can use our methods to conduct targeted urban forest management to maximize urban forest benefits received by residents.
... Software tools, also developed in the US, such as "i-Tree" (I Tree, 2014), and tree canopy cover data from remotely sensed imagery are now available to assist cities around the world gather evidence for planning and managing urban trees. Several studies and sampling techniques have identified and accounted for spatial heterogeneity of urban tree canopy cover across different land-uses and tenures ( Dobbs et al., 2013;Escobedo and Nowak, 2009;Jaenson et al., 1992;Kirkpatrick et al., 2011;Maco and McPherson, 2003;Nowak et al., 2008a;Nowak et al., 2008b;Sanders, 1984). Others have explored the influence of biophysical, land-use change and socio-economic factors on this uneven distribution and consequent inequity in urban ecosystem services provision ( Conway and Bourne, 2013;Gong et al., 2013;Heynen et al., 2006;Ives and Kendal, 2014;Kendal et al., 2012;Landry and Chakraborty, 2009;Pham et al., 2013;Wolch et al., 2014). ...
... Within residential suburbs, 1 where tree canopies covered 35.3% of the land area, most tree cover was on private land. Brisbane's residential suburbs have generally grown a lot greener over the last 60 years ( Plant, 1996a), including an estimated doubling of the proportion of properties with one or more adjacent street trees between 1961 and 2006 ( Kirkpatrick et al., 2011). By 2010, the canopies of street trees growing within the footpath zone of road reserves, hereafter referred to as "footpath tree canopy cover", covered an average of 35% of the total footpath zone area. ...
Trees along footpath zones (or verges) grow on the āfront-lineā of urban forest ecosystems, increasingly recognised as essential to the quality of human life in cities. Growing so close to where residents live, work and travel, these street trees require careful planning and active management in order to balance their benefits against risks, liabilities, impacts and costs. Securing support and investment for urban trees is tough and robust business cases begin with accurate information about the resource. Few studies have accounted for spatial heterogeneity within a single land-use type in analyses of structure and composition of street tree populations. Remotely sensed footpath tree canopy cover data was used as a basis for stratification of random sampling across residential suburbs in the study area of Brisbane, Australia. Analysis of field survey data collected in 2010 from 80 representative sample sites in 52 suburbs revealed street tree population (432,445 Ā± 26,293) and stocking level (78%) estimates with low (6.08%) sampling error. Results also suggest that this population was transitioning to low risk, small-medium sized species with unproven longevity that could limit the capacity of the Brisbane's Neighbourhood Shadeways planting program to expand from 35% footpath tree canopy cover in 2010, to a target of a 50% by 2031. This study advances the use of contemporary techniques for sampling extensive, unevenly distributed urban tree populations and the value of accurate resource knowledge to inform evidence-based planning and investment for urban forests.
... Melbourne is a useful place to study the drivers of tree change as there is high-quality data available across time on land use and land tenure, and a highly regulated urban planning process. Historically, there has been great variation in tree cover (Kirkpatrick et al., 2011). There is rapid change within the existing urban fabric, both through active municipal tree planting programs at the same time as perceived loss of tree canopy in some neighbourhoods as a result of increases in housing size and density promoted by policies to increase population densities (Hall, 2010). ...
Urban tree canopy cover (UTC) is a simple, and common, measure of urban forest resource. Urban infill development is likely to lead to losses in UTC under private tenure, at a time when local governments are setting ambitious targets to increase UTC overall. Simple, statistically rigorous methods are required to benchmark and track change in UTC, whilst identifying which land-use types or tenures experience change.
We estimated UTC in six Melbourne suburbs in 2010 and 2015 by randomly sampling 2000 points across public land, public streetscapes and private land. We were able to detect a net change in UTC of <2% over five years to a 95% level of confidence. A significant net decrease in UTC (ā2.4%) was only detected in one of the six suburbs. Two suburbs had a net increase in UTC by +2.7% over five years. On private land, there was often areas of UTC loss, but this was generally offset by canopy gain in other areas of the private realm as well as in streetscapes and public land. Losses in UTC on private land were mainly due to tree removal, with or without subsequent construction works.
This study describes a simple, but statistically rigorous, method to quantify UTC change and the drivers of change in different land-use types and tenure. Despite studying two suburbs will high rates of infill development, only one suburb showed evidence of net UTC decrease. The ādynamic equilibriumā in UTC, whereby canopy losses area approximately offset by concurrent canopy gain, means that ambitious targets being set by local governments to increase UTC may be difficult to achieve without changes in tree protection and infill development policy and planning.
... In low-density cities with extensive suburban areas, private gardens represent a large proportion of the overall urban green infrastructure network (Cameron et al., 2012;Ghosh & Head, 2009;Loram et al., 2007). Private residential land in Sydney provides 43% of foliage cover and 77% of Australian capital city residences have one or more trees in their private gardens (Kirkpatrick et al., 2011;Lin et al., 2015). More than 50% of total greenspace in Dunedin, New Zealand comes from private gardens (Mathieu, Freeman, & Aryal, 2007) and that figure is 35-47% in England (Loram et al., 2007), where 87% of houses have access to a private garden (Gibbons et al., 2014). ...
The ever-increasing process of urbanisation across the globe will have major implications for the environment, biodiversity and health and well-being of urbanites. There is growing recognition of greening as a promising planning tool in tackling problems associated with urbanisation, including biodiversity loss and heat island effects. Domestic gardens constitute a substantial proportion of greenspaces in suburban societies, and gardens and gardening have social, psychological, physical, economic, and environmental benefits. However, the relationship between gardens and other nondomestic greenspaces is not well understood.
Drawing on a qualitative study with residents in suburban Melbourne, this paper seeks to discuss a number of questions about the relationship of domestic gardens to non-domestic greenspaces. Questions the paper explores include how residentsā use of domestic gardens might impact their use of other neighbourhood greenspaces and what this relationship might imply for planning and neighbourhood design. Other questions considered are: Is the balance between the proportion of gardens and other greenspaces important for urban environments? Can this balance resolve the issue of inequality in terms of access to greenspaces in lower income neighbourhoods?
The discussion raised by these questions can shed some light on the balance needed for different typologies of greenspaces in suburban societies. A better understanding of the relationship between domestic gardens and other urban greenspaces provides professionals in planning and landscape design with evidence on which to base neighbourhood planning and greening interventions.
... Relationship between mean annual precipitation of the proportion of regionally native tree species (P < 0.001). species from other biomes and biogeographical provinces in some cities is in contrast to hypotheses of homogenization (Yang et al., 2015) but is consistent with other warm dryland cities in Australia (Kirkpatrick et al., 2011) and subtropical Hong Kong (Jim & Zhang, 2015). As our assessment is limited by the coarse-scale analysis of species native ranges, improved range delineation will allow a more complete evaluation of plant origins. ...
AimWe propose and test a climate tolerance and trait choice hypothesis of urban macroecological variation in which strong filtering associated with low winter temperatures restricts urban biodiversity while weak filtering associated with warmer temperatures and irrigation allows dispersal of species from a global source pool, thereby increasing urban biodiversity. LocationTwenty cities across the USA and Canada. Methods
We examined variation in tree community taxonomic diversity, origins and production of an aesthetic ecosystem service trait in a cross-section of urban field surveys. We correlated urban tree community composition indicators with a key climate restriction, namely mean minimum winter temperature, and evaluated alternative possible drivers: precipitation, summer maximum temperature, population size and the percentage of adults with a college education. ResultsSpecies accumulation curves differed substantially among cities, with observed richness varying from 22 to 122 species. Similarities in tree communities decreased exponentially with increases in climatic differences. Ordination of tree communities showed strong separation among cities with component axes correlated with minimum winter temperature and annual precipitation. Variation among urban tree communities in richness, origins and the provisioning of an aesthetic ecosystem service were all correlated with minimum winter temperature. Main conclusionsThe urban climate tolerance and trait choice hypothesis provides a coherent mechanism to explain the large variation among urban tree communities resulting from an interacting environment, species and human decisions. Reconciling the feedbacks between human decision making and biophysical limitations provides a foundation for an urban ecological theory that can better understand and predict the dynamics of other linked biotic communities, associated ecosystem dynamics and resulting services provided to urban residents.
... There was no consideration of the density of tree canopy cover in our roof analysis or the different canopy and leaf architecture of different tree species, which may explain some of the variability in the results. In a previous investigation by Kirkpatrick et al. [53], it was estimated that 7% of garden trees in Sydney were deciduous. It should also be recognised there are important trade-offs to be considered, with several studies in the northern hemisphere investigating the interactions between tree shade and solar access for rooftop photovoltaic systems [54][55][56]. ...
In many parts of the world, urban planning has a renewed focus on addressing the multiple challenges associated with population growth and climate change. Focused on local needs and priorities, these planning processes are raising tensions between more compact and dense urban form to reduce energy use and associated emissions and the provision of urban green infrastructure for ecosystem services and climate adaptation. In this study, we investigated the spatial distribution of green infrastructure at the neighbourhood scale in Sydney, Australia and examined how a mix of landscape types (pavement, bare soil/dry grass, green grass, and tree cover) affect temperature variation in three important locations for urban residentsāaround the home, in the roads and footpaths where people walk, and in parkland areas. Considering that residential and parkland areas contribute to the majority of green space in Sydney, it is important to understand how changes in landscape mix within these three neighbourhood areas will affect local temperature for urban residents. For residential houses, it was found that the percentage of tree canopy cover around the house had a significant negative relationship (p = 0.002) with surface temperatures of rooftops where greater tree cover led to lower rooftop temperatures. In streetscapes, both the percentage of tree cover (p < 0.0001) and the percentage of green grass (p < 0.0001) within the road segment had a significant negative relationship with the surface temperature of the road pavement. In the parks, the percentage of pavement (p < 0.0001) and the percentage of bare soil/dry grass (p < 0.0001) showed a significantly positive trend with land surface temperatures where greater land cover in the form of pavement and bare soil/dry grass led to higher temperatures. Collectively, these findings highlight the importance of promoting or reducing certain landscape covers depending on the land use type in order to maximise the cooling potential of green infrastructure.
... Some classes are clearly separated by city; Class VII (new London streets) and Class VIII (new Halifax streets) represent very different assemblages, comprising both native and non-native species. Other plots are set apart according to development decade, indicating that both spatial and temporal factors influence the tree-species composition of streetscapes (Kirkpatrick et al. 2011). ...
Determining how suburbanization shapes tree-species composition and diversity is vital in Canadian and most nationsā cities, as suburban and peri-urban areas continue to grow faster than any other region. These areas, characterized by various land types and uses, represent differences in management and governance, jurisdiction, planting practices and species selection, and professional and political agendas. Such complexities emphasize the importance of exploring the influence of various environmental and location attributes of suburban neighbourhoods. Using hierarchical cluster analysis to classify urban forest species assemblages, we found that location attributes such as land type, development decade, and geography are influential on species composition and diversity ā but only to an extent. We found that street-tree assemblages were classified more distinctly than remnant woodlands, which were in turn more distinct than tree communities found on residential properties. Residential land types had a high degree of species heterogeneity, highlighting the importance of not only considering the location attributes chosen for this study, but also including socioeconomic and cultural variables in future ecological classification schemes. Identifying drivers of species composition and diversity is useful for developing and implementing forest management strategies for urban and peri-urban areas, as different species assemblages give rise to different challenges and management opportunities, as well as varying quantities of ecosystem services, values, and benefits.
... This led to the call for more studies that include multiple cities, regions, and countries (McDonnell and Hahs, 2013). In recent years, there is a steady increase in the number of studies covering multiple cities and regions (Avolio et al., 2015;Blood et al., 2016;Kendal et al., 2014;Kirkpatrick et al., 2011;Nowak, 2012;SaebĆø et al., 2005;Sjƶman et al., 2012). In North America, species compositions of planted tree populations in 14 cities in the United States and Canada were analyzed (Nowak, 2012). ...
A good knowledge of species diversity is essential for urban forest planning and management. In this study, we analyzed species diversity of urban forests in China using data synthesized through a systematic review. Our analysis showed that 3740 taxa of woody plants at species level and below have been reported in urban forests in 257 cities. Merging to the species level, there were 2640 species, including 1671 trees, 743 shrubs, and 226 lianas. Salix babylonica L. was the most widely distributed urban tree species in China. Overall, native species accounted for 76.02% of the observed species while the rest were exotic species. Inside cities, parks contained more species than other types of land use. Among cities, composition similarity of urban forests decreased as spatial distances among them increased. Besides, there was a latitudinal pattern in compositional similarity of urban forests in China. The relatively low ratio of the number of woody plant species in urban forests to these naturally distributed in China indicates that there is plenty of room for increasing species diversity of urban forests in China. However, cautions must be taken to avoid increasing compositional similarity of urban forests in China at the same time.
... In urban landscapes, the abundance and diversity of plants are positively related with neighborhood income. Higher income neighborhoods tend to have greater abundance and more diverse public and private green spaces, whereas the poorest neighborhoods tend to have lower quantities and less diverse ones (Kirkpatrick et al., 2011;Clarke et al., 2013). This segregation in the spatial distribution of vegetation may be not only present in large cities in more developed countries, but also in mediumsized cities in less developed countries (e.g., cities in Latin America, de la Maza et al., 2002;Borsdorf and Hidalgo, 2010). ...
Tree diversity is one of the most important components of urban ecosystems, because it provides multiple ecological benefits and contributes to human well-being. However, the distribution of urban trees may be spatially segregated and change over time. To provide insights for a better distribution of tree diversity in a socially segregated city, we evaluated spatial segregation in the abundance and diversity of trees by socioeconomic group and their change over a 12-year period in Santiago, Chile. Two hundred vegetation plots were sampled across Santiago in 2002 and 2014. We found that overall abundance and diversity of urban trees for the entire city were stable over 12 years, whereas species richness and abundance of native tree species increased. There was segregation in tree species richness and abundance by socioeconomic group, with wealthier areas having more species and greater abundance of trees (for all tree species and native species) than poorer ones. Tree community composition and structure varied with socioeconomic group, but we found no evidence of increased homogenization of the urban forest in that 12 years. Our findings revealed that although tree diversity and abundance for the entire city did not change in our 12-year period, there were important inequities in abundance and diversity of urban trees by socioeconomic group. Given that 43% of homes in Santiago are in the lower socioeconomic areas, our study highlights the importance of targeting tree planting, maintenance and educational programs in these areas to reduce inequalities in the distribution of trees.
... Lyytimā¬ aki and Sipilā¬ a (2009) referred to ecosystem disservices as functions of ecosystems that are perceived as having negative effects on human well-being. von Dā¬ ohren and Haase (2015) reviewed 103 papers related to disservices, mostly from urban and agriculture ecosystems, and grouped them into 4 categories: (1) ecological impact: disservices that negatively affect ecosystem structure, processes and/or services, e.g., bio-emissions (Escobedo et al., 2011;Franck et al., 2014;Seamans, 2013); (2) economic impact: disservices that negatively affect socio-economic structure and processes, e.g., maintenance cost for urban green areas (Escobedo et al., 2011;Kirkpatrick et al., 2011;Nowak, 2012); ...
Urban ecological infrastructures (UEIs; e.g., parks, beaches, rivers, forests, and woodlands) provide important ecosystem services (ESes) to urban ecosystems. Understanding the covariance of multiple ESes and disservices and their associations with social economic factors is a precondition of ecosystem management. Previous studies have mainly focused on ESes and tradeoffs among multiple ESes, whereas disservices and their associations with ESes have seldom been addressed. In this study, we took public urban parks, an important component of UEIs as well as the basic unit for management, as a case study and explored the ESes and disservices of different types of parks and the delivery of ESes to different social economic strata based on 187 plot inventory data. The results showed that the actual dominant ESes of four types of parks differed from both the expectations of planners and the demands of residents. Positive correlations existed among ESes and disservices (e.g. bio-emissions and air pollution reduction). Population density was positively related with several ESes; Distance to urban center was negatively associated with C storage, bio-emissions, and aggregative ES indicators; Wealthy areas had better performance in terms of C storage and aggregative ES indicators. Major challenges for the four types of parks and measures to coordinate ESes and disservices are discussed. Multiple stakeholder involvement, ES provision for low income populations, and the protection of parks in peri-urban and central urban areas are suggested.
... The weak socio-economic and demographic differentiation between the vegetable floristic groups (Table 1) contrasts with the strong social differentiation shown both for overall garden floristic groups (Kirkpatrick et al., 2007) and the propensity to grow trees in gardens (Kirkpatrick et al., 2011). ...
Food production is of symbolic and practical importance in sustainable cities. Vegetable gardening in public spaces and community gardens is better understood than the same activity on private residential property. In suburbanised western cities most vegetable production is likely to be on private blocks. To increase vegetable production in cities, we need to understand private vegetable growing. We used a questionnaire administered in person with a diverse sample of 101 gardeners in Hobart, Tasmania, Australia to determine variation in gardens, gardening practices and gardener motivations, relationships between them, and potential for planning and other interventions to increase domestic vegetable production. Vegetable gardens varied from highly species-rich to species-poor and from staple production to expressions of culinary fashion. Gardening practices varied from integrated, organic and displayed, to strongly constructed and reliant on synthetic inputs. While all respondents were motivated to grow vegetables for pleasure, many were activists who wished to promote social change, while others wished to ensure affordable access to vegetables or to improve health. Activist gardeners used integrated organic or permacultural practices and produced highly complex garden outcomes. With the exceptions of the activists and food fashionistas, garden type, gardening practice and gardener motivation were not strongly interlinked. A large majority of respondents identified family members as important sources of information and inspiration. Gardeners without family role models were either influenced by new food cultures or were on low-incomes and wanted affordable access to vegetables. This latter group could be expanded through appropriate education and incentives.
... Indeed, the practice of urban forestry and greening has in many cases been given significant support through policy and legislation (Feng and Tan, 2017;Tan et al., 2013). Ongoing support for relevant policy and governance continues to be informed by analyses of spatiotemporal changes in tree cover across both private and public land-use types (Daniel et al., 2016;Kirkpatrick et al., 2011) and through innovative assessments of resident preferences (Plant et al., 2017). In light of the anthropocentric nature of existing assessments, more can be done to quantify less-tangible tree benefits and costs (i.e. ...
Understanding the benefits provided by urban trees is important to justify investment and improve stewardship. Many studies have attempted to quantify the benefits of trees in monetary terms, though fewer have quantified the associated costs of planting and maintaining them. This systematic review examines the methods used to jointly analyse the costs and benefits of trees in the urban landscape, assesses the relative balance of benefits and costs, and attempts to understand the wide variation in economic values assigned in different studies. The benefits most frequently studied are those related to environmental regulation and property values, and the available data show that these usually outweigh the costs. Aesthetic, amenity, and shading benefits have also been shown to provide significant economic benefits, while benefits in terms of water regulation, carbon reduction and air quality are usually more modest. Variation in benefits and costs among studies is attributed largely to differences in the species composition and age structure of urban tree populations, though methodological differences also play a role. Comparison between studies is made difficult owing to differences in spatiotemporal scope, and in the way urban forest composition and demographic structure were reported. The overwhelming majority of studies concern deciduous trees in Northern America, and much less is known about urban forests in other regions, especially in the tropics. Future work should thus seek to fill these knowledge gaps, and standardise research protocols across cities. In light of ambitious goals in many cities to increase tree cover, ongoing advances in valuation methods need to provide a more comprehensive accounting of benefits and costs, and to better integrate economic assessment into the decision-making process.
... The most commonly known urban green space elements in cities include parks and reserves, sporting fields, stream and river banks, greenways and trails, street trees, and nature conservation areas [256] and private gardens. The green landscape could vary in size, vegetation cover and type, biota species varieties, natural quality, proximity to public transport, facilities, and services [56,79,113,206,207]. The urban green space provides a wide range of ecosystem services that could improve the living standards for citizens. ...
The urban green landscape is considered one of the pivotal elements of a sustainable
city. The green spaces significantly promote the city dwellersā physical and psychological health
and social well-being and the city economy and preserve the surrounding natural environment.
Although scientific papers have widely investigated the concepts of sustainable cities and individual
elements of urban landscapes, the general concept of an urban landscape that encompasses
all the known influencing factors of urban greenery with respect to integrated sustainability and
water scarcity planning and development has not yet been explored. This chapter reviews a plethora
of publications from various study fields, including urban planning, hydrology, water management,
ecology, plant physiology, and sustainability, to present a general picture of a sustainable
water-wise green landscape. An overview of the current state of findings on urban green space
benefits is provided. Then, the concepts of sustainability in general and the eco-city in particular
are presented. The proposed modern strategies and solutions for urban green space planning and its water demand estimations are discussed. Finally, a number of multidisciplinary approaches and
present irrigation systems in urban areas under drought stress for water-efficient and enduring
urban greenery are examined.
... The studies mostly reported the existing status of the diversity and composition of the street trees in the urban streetscape. There is little knowledge to demonstrate the changes in the diversity and composition of cultivated trees in urban streets (Kirkpatrick et al., 2011), particularly the changes in the diversity and the composition of exotic and native species along different socioeconomic gradients of the streets of any mega city. Nevertheless, many studies reported existing variations in the diversity and the composition of trees along different socioeconomic gradients of urban landscape (Hope et al., 2003;Kinzig et al., 2005;Kuruneri-Chitepo and Shackleton, 2011). ...
... In low-density cities with extensive suburban areas, private gardens represent a large proportion of the overall urban green infrastructure network (Cameron et al., 2012;Ghosh & Head, 2009;Loram et al., 2007). Private residential land in Sydney provides 43% of foliage cover and 77% of Australian capital city residences have one or more trees in their private gardens (Kirkpatrick et al., 2011;Lin et al., 2015). More than 50% of total greenspace in Dunedin, New Zealand comes from private gardens (Mathieu, Freeman, & Aryal, 2007) and that figure is 35-47% in England (Loram et al., 2007), where 87% of houses have access to a private garden (Gibbons et al., 2014). ...
The increasing process of urbanisation has major implications for the environment, biodiversity, and health and well-being of urban residents. Empirical evidence for urban greening benefits suggests that it is an appropriate planning and policy approach for tackling some of the problems associated with urbanisation, including biodiversity loss and heat island effects. Gardens on private residential lots represent a substantial proportion of greenspaces in low density cities with extensive suburban areas. Drawing on a qualitative study of residents in Sunshine North, Melbourne, Australia, this paper discusses three questions about the relationship of private gardens to public greenspaces:
1) how does residentsā use of private gardens impact their use of other neighbourhood greenspaces;
2) can private gardens address inequality of access to greenspaces in lower income neighbourhoods; and,
3) what does this imply for planning and neighbourhood design?
Contrary to previous research, the findings did not show a meaningful relationship between residentsā use of their gardens and local greenspaces, and further, that large yards and gardens do not substitute for poor access to local greenspaces. The paper concludes that policy makers and planners cannot assume private gardens and public greenspaces are interchangeable. While private gardens and local greenspaces can both provide positive benefits to residents, private gardens do not act as a substitute for local greenspaces in
neighbourhoods of varying socio-economic status.
... Moreover, the urban forests in Greater Melbourne are characterized by an uneven treecanopy distribution which is related to neighborhood age, income, and education level [70] [71] . Climate change represents a huge challenge for Greater Melbourne's urban forests, which has become more evident in recent decades along with the increased drought, heatwave, and flooding events [72] [73] . Many local governments in the area are creating a metropolitan urban forest strategy that integrates and coordinates efforts across city councils ā” . ...
... The urban areas incorporate different types of spaces on which trees are planted. These spaces represent the differences in land use, tree planting practices, species selection decisions, and ownership (Kirkpatrick, Dainels & Davison, 2011;Bourne & Conway, 2014). In the past decade, there were many local authorities and property developers in Malaysia who planted the trees for greening programs and aesthetic purposes (Sreetheran et al., 2006;Abd Kadir & Othman, 2012;Hasan, Othman & Ismail, 2018). ...
Most urban trees need a periodic process such as branch pruning to fulfil the requirements of the quintessential characteristics related to its longevity, safety, and removal, based on specific reasons. These processes contribute towards the increment of waste capacity and the cost of maintenance. Therefore, waste should be managed properly since might become a valuable resource for economic benefit. Thus, the study aims to identify the value of urban tree species whereas their waste can be utilised as an alternative for furniture lumber. Seven major roads were selected in Kuala Lumpur, Malaysia as the areas for the case study. Methods such as literature review and tree inventory were performed to gather significant data. The results acknowledged four valuable urban tree species that can be utilised as furniture lumber. These trees are under the big tree category within 10 to 45 m in height with more than 1m diameters of bolewood, which is their waste is suitable for lumber production. The finding also provides good practice in managing the waste of urban trees for economic worth.
... Due to different background in social, cultural, political aspects, geographical distribution of urban parks have displayed distinctively diversified situations (Kirkpatrick et al., 2011;Song et al., 2020). The influencing factors of urban park spatial layout are also the focus of previous studies. ...
Urban parks are vital ecological recreational places, and their spatial evolution has a certain influence on the ecological environment and quality of citizensā daily life. Taking Beijing as an example, this paper firstly explores the dynamic evolution of urban parks in Beijing by comparing spatial distribution characteristics in three time points of 2005, 2010 and 2017. Besides changes in number and area, the spatial structure and accessibility are examined by the methods of directional distribution, kernel density estimation and network analysis. Then three-factor analysis method is used to explain the evolution mechanism. The results reveal that there exist obvious and continuous growths in urban parks regardless of quantity, area or accessibility. According to the core-periphery spatial distribution pattern, Beijing has gradually formed a systematic green recreational network, and the service area of urban parks by walking within 30 min is 58.6% of total area. Stability factors, dynamic factors and random factors play important roles during the spatial evolution of urban parks through restraint mechanism, supply-demand mechanism and triggering mechanism respectively. The findings offer both theoretical construct and policy recommendations for the development and sustainability of urban parks in Beijing and other rapidly urbanizing cities with high population densities.
... Many studies have documented the cornucopia of perceptions that people have in relation to trees. Such perceptions include the costs and benefits (Hull 1992;Lohr et al. 2004;Jorgensen and Anthopoulou 2007;Kirkpatrick et al. 2011;Kirkpatrick et al. 2012), urban vegetation and landscape preferences (Schroeder 1982;Schroeder 1983;Talbot and Kaplan 1984;Jorgensen et al. 2002;Roovers et al. 2006;Zheng et al. 2011), safety in and around urban green spaces (Schroeder and Anderson 1984;Shaffer and Anderson 1985;Jorgensen et al. 2002;Bjerke et al. 2006;Jansson et al. 2013), preferred species characteristics (Summit and Sommer 1999;Nelson et al. 2001;Lohr and Pearson-Mims 2006;Gerstenberg and Hofmann 2016), and the potential risks that they can pose (Wyman et al. 2012;Kirkpatrick et al. 2013;Koeser et al. 2015;Klein et al. 2019). The latter has been addressed the least. ...
Professional judgment is derived from a personās intuition, training, and level of expertise. When exploring the influence that expertise has on the process of tree risk assessment, it is helpful to approach the topic in relation to its impact across various related fields and disciplines. This paper reviews the effects of arboricultural and tree risk assessment training on the assessor and overall tree risk assessment methodology through the lens of professional judgment and decision making. Additionally, the topic of risk perception is explored based on how it can affect decision making. Concepts and theories related to risk perception are applied to arboriculture and tree risk assessment to provide additional insight into how subjectivity and personal bias may affect recommendations, mitigation, and the overall management our urban forests. The review finds that an individualās perception of a risk can be equally as influential as the reality of the risk on the decision-making process, recommendations, and subsequent outcomes of an assessment. Furthermore, experts, similar to novices, are susceptible to the influence of perceived risk. Much of the available research has suggested that the acquisition of professional expertise (i.e., previous experience, training, and accreditation) can result in decision making that is more closely tied to the reality of a risk. Ultimately, a great deal remains unknown regarding our understanding of professional expertise and its influence on the tree risk assessment process.
... Among these, most studies on the floristic patterns of street trees are generally focused on a single city, such as Syracuse (USA) (Sanders 1981), Hong Kong (Jim 1999), Rome (Attorre et al. 2000), Berlin (Zerbe et al. 2003), Taipei (Jim and Chen 2009), Bangalore (Nagendra and Gopal 2010), and Montreal (Apparicio et al. 2012). Only a limited number of studies present comparative analysis of the biodiversity of street trees across large areas or countries, such as Australia (Kirkpatrick et al. 2011), South Africa (Kuruneri-Chitepo and Shackleton 2011), Denmark (Sjƶman et al. 2012; Thomsen et al. 2016), Sweden (Sjƶman et al. 2012), Norway (Sjƶman et al. 2012), andCalifornia (McPherson et al. 2016). ...
Street trees are key elements in urban ecosystems from several points of view, and different species can have different functions (i.e., ecological, socio-economic). As such, a careful biodiversity assessment is pivotal. We evaluated urban street trees in 15 Italian cities along a geographical and bioclimatic gradient. The data was obtained from scientific literature and Garden Service Offices of the cities. The distribution patterns of the species were analyzed in terms of taxonomy, chorology, and tree size. We registered 277 tree species belonging to 48 families. The species richness is very variable in analyzed cities, and it is not directly correlated with the city's size. Only three species (Platanus Ć hispanica, Celtis australis and Quercus ilex) are common to almost all cities, while 41.52% of the species are present only in one city. The comparative analysis of species, considering the floristic and city distribution, showed different results, highlighting Pinaceae as the most common family. The chorological analysis shows a predominance of exotic species and a good relationship with the bioclimatic conditions of cities. A selection of the species, as street trees to maximize their ecological and socio-economic functions, is pivotal in urban landscaping and green management.
... The formalisation and popularisation of tree care and management in western governmental systems that we see today in Australia is partly influenced by the 1930s Dutch Elm Disease epidemic in the U.S.A., and the rise in professional urban arboriculture it inspired (Jonnes 2016). The goals and objectives of urban forestry strategies in Australia have been driven strongly by professional expertise in the form of arborists (Kirkpatrick, Daniels, and Davison 2011) and quantitative assessment of urban forest cover (Jones and Instone 2016). The approach of 'leaving it to the experts' (Dryzek 2005, 62) at the nexus of science and professional administration can reinforce a positivist, apolitical and universal discourse around the benefits of urban trees that requires more unpacking (Anguelovski et al. 2020). ...
Global enthusiasm for nature in cities is at high point. Australia is no exception, where there is a great deal of policy momentum and research interest in urban greening. The challenges presented by increasing urban heat associated with climate change, greater awareness of the potential social, physical and psychological benefits of exposure to ecologies for people, and recognition of cities as vital habitats for more-than-humans are central tenants of urban greening enthusiasm. Yet, there is a need for a more critical lens on urban greening in Australia. One that interrogates the purported normative, apolitical and instrumental benefits of greening, to position greening within a trajectory of the power relations, settler-colonialism, socio-ecological processes and capital flows that constitute the urban. This editorial introducing the special issue on urban greening politics explores how different conceptions of urban natures ā green space, urban forestry and green infrastructure ā have been put to work, before outlining the potential of āurban greeningā as the terminology for a more politically sensitive and process-orientated framing. The editorial concludes with a summary of the contributions to the special issue.
... The urban forest within The City of Melbourne consists of approximately 70,000 trees (CoM, 2012). Melbourne and its urban forest have experienced significant droughts and heatwaves in recent decades, which have impacted the tree population in various ways, notably in shortening the life expectancy of many mature trees (Kirkpatrick et al., 2011;May et al., 2013). The impact of drought is most notable in the dominant exotic tree species, many of which are now approaching the end of their useful life expectancy (City of Melbourne, 2012), with many programmed for removal and replacement J o u r n a l P r e -p r o o f in coming years. ...
Many cities face a struggle to reconcile ambitious tree canopy cover targets with urban development pressures. Canopy cover in The City of Melbourne, Australia, which has a target of 40% canopy cover on public land by 2040, was analysed together with individual tree removal data, with particular focus on how many street trees were removed near major development sites between 2008 and 2017.
We observed major gains and losses of canopy, resulting in small net changes.
Our analyses showed a net gain in tree canopy cover in public streets and a net loss of canopy cover in public parks and private properties. The most frequently removed trees in both public parks and streets were small (<15 cm stem diameter). In contrast, more large, exotic trees were removed from public parks than public streetscapes. These large park trees represented a small proportion of total tree removals, but had larger stem basal areas and therefore large canopies. From 2008 to 2017, almost 2000 street trees were removed within 10 m of major development sites, equivalent to almost 20% of all street trees removed in that time period, but this constituted only 8% of streetscape tree canopy cover losses.
These findings suggest that in The City of Melbourne, mature tree succession and removal in parks has the greatest potential to hinder the achievement of canopy cover targets. Canopy cover gains could be maximised through improvements in the establishment and survival of replacement trees in both parks and streetscapes. The protection of the existing urban forest, through policy and practice, will also be critical for the retention and enhancement of tree canopy cover.
... The environmental injustice associated with the uneven distribution of public green space has been well documented (e.g. Jenerette et al., 2011;Kirkpatrick et al., 2011). In the scientific literature, a higher percentage of vegetation is usually associated with greater social advantage, e.g. the 'ecology of prestige' (Hope et al., 2003;Grove et al., 2006), while in this study a higher percentage of vegetation is associated with greater social disadvantage. ...
... While canopy cover is desirable to maximise ecosystem services (Lin et al., 2016;Richards and Edwards, 2017), reaching and maintaining TCC goals can be chal lenging. This is because canopy cover is dynamic, changing over time and space (Kirkpatrick et al., 2011;Krafft and Fryd, 2016;Nowak and Greenfield, 2012;Steenberg et al., 2018). Trees are subject to growth and removal over time and spatially, they are not generally equitably distributed throughout cities due to physical, socio-economic, ecological, and policy factors (Escobedo and Nowak, 2009;Fan et al., 2019;Heynen and Lindsey, 2003;Nesbitt et al., 2019). ...
Urban redevelopment influences urban forests, with consequences for ecosystem service provision. Better understanding the effect of redevelopment on trees in cities can improve management and inform policy, thus having positive effects on ecosystem service provision and human wellbeing. This study quantified the effect of residential property redevelopment on canopy cover change in Christchurch, New Zealand. By applying an object-based image analysis (OBIA) technique to aerial imagery and LiDAR data, this study delineated tree canopy cover city-wide in 2011 and again in 2015 and then spatially quantified changes in city-wide canopy cover between 2011 and 2015. Changes in tree canopy cover were also determined at a finer scale, that of the meshblock, a geographic boundary used for census purposes. The results show a small absolute magnitude of city-wide tree canopy cover decline, from 10.84% to 10.28% between 2011 and 2015, but a statistically significant decrease in meshblock-scale mean tree canopy cover. Tree canopy cover losses were more likely to occur in meshblocks containing properties that underwent redevelopment, but the loss was insensitive to the density of redeveloped properties within meshblocks. These findings show that property redevelopment is an important influencer of urban forest dynamics.
... Areas of socioeconomic advantage are amongst older suburbs, in the case of Brisbane, where early street tree plantings along wide verges consisting of monocultures of fashionable species (Plant 1996) have persisted to provide both mature and less diverse streetscapes. Though others have found higher education and income levels can be strong predictors of species richness (Escobedo et al., 2015b) and support for street tree planting (Conway and Bang 2014), at the neighbourhood scale, there are clearly complex interactions between existing species diversity, socio-economics, patterns of development and other factors (Rosiers et al., 2007, Kirkpatrick et al., 2011, Lowry et al., 2012, Flint et al., 2013, Ives and Kendal 2014, Shakeel and Conway 2014) that can influence resident tolerance to streetscape diversity at the finer scale of nearby streets, reinforcing the need for local assessments (Williams 2002). ...
Municipalities are setting targets for increasing street tree species diversity to support resilience and enhance the supply of ecosystem services from the urban forest. Assessments of street tree composition and structure, and consequent vulnerability to the stresses of urban climate change, pests and disease offer guidance for such targets. However, assessing local resident preferences towards species diversity within streets is also important to achieving such targets. Much of the research on street tree preference to date has focused on resident preferences for individual street tree characteristics, without reference to collective/contextual characteristics such as species diversity. We infer resident preferences for collective street tree features, including species richness, from nearby house sale prices in the city of Brisbane, Australia. While home-buyers were willing to pay a premium for houses in streets with mature and aged trees, their tolerance for mixtures of species was limited to no more than six species nearby. Tolerance also varied within the city with greater sensitivity to mixtures of species in locations of greater socioeconomic advantage. These findings suggest that increased diversity will not automatically be accepted by the community. Municipalities need to be cautious in their approach to increasing tree species diversity at finer scales, like streetscapes, within the urban forest.
... Urban parks and woodlands are more often located in wealthier neighbourhoods (Poudyal et al., 2009) and require leisure time to enjoy as they can be located some distance from urban residents' homes (Harnik, 2010). The size and abundance of trees on private property are often higher in high-income neighbourhoods (Kirkpatrick et al., 2011) and there is evidence that lower levels of canopy cover across all land ownership types are more often associated with lower-income and racialized neighbourhoods (Landry and Chakraborty, 2009;Nesbitt and Meitner, 2016;Schwarz et al., 2015). In some cases, socioeconomically disadvantaged and racialized urban residents are less likely to engage in urban vegetation stewardship activities, to participate in urban forestry decision making, and to have control over urban vegetation resources (Buijs et al., 2016;Heynen, 2003). ...
Urban vegetation, and in particular urban forests, provide a wide range of ecosystem services to urban societies and may thus be classified as environmental goods. Their status as goods suggests that urban societiesā interactions with urban vegetation should be subjected to equity analyses to determine the fairness of such interactions. However, despite good evidence that the distribution and governance of urban vegetation are inequitable in many cases, there is no urban forestry-specific framework for analysis of urban green equity: how we access and govern urban vegetation. To begin to fill this gap, this paper reviews research in the fields of ethics, social and environmental justice, political ecology, and urban forestry research and practice, with a focus on urban forestry, and presents a discussion of the dimensions and sub-dimensions of urban green equity. The principal dimensions that emerged from the analysis were (1) the spatial distribution of urban vegetation, and (2) recognition in urban vegetation decision making, defined here as acknowledgement of participantsā difference, existence and validity in decision-making processes, both formal and informal, and the inherent inclusion and power associated with that acknowledgement. Sub-dimensions of spatial distribution included temporality, condition, preference, and ownership, and sub-dimensions of recognition included representation and procedure, and the desire and ability to participate in decision making processes. These dimensions provide a framework for future urban green equity analyses and can help inform public conversations on urban green equity. Access the full article here until September 6, 2018: https://authors.elsevier.com/a/1XPKj5m5d7hjt6
... Regarding tree planting in particular, a study in Missouri shows that residents from high-income and high-education areas were more willing to fund street tree programs (Treiman & Gartner, 2006). In Hobart (Australia), poor neighborhoods had a hostile reception to new tree plantings, while wealthy suburbs exhibited no signs of objection (Kirkpatrick, Daniels, & Davison, 2011). Another study from Toronto finds that residential associations that are more involved in maintaining urban forest are generally found in higher income neighbourhoods, are composed of homeowners and live in more recently built dwellings (Conway et al., 2011). ...
Green alley programs, increasingly promoted by cities in North America, generally aim at transforming alleys into green infrastructure, ensuring ecosystem services, enhancing road safety and allowing appropriation by local residents. Yet, there is a dearth of fine-grained research on locational patterns and characteristics of green alleys. We seek to assess the outcomes of a green alley program in the City of MontrĆ©al (Canada), by examining the socio-spatial distribution of green alleys, their most common features, and their scores (measured by summing the number of features). We used the 2016 census data at the dissemination area level and evaluated 341 green alleys (summer 2020) by a grid composed of 45 items. Green alleys in MontrĆ©al are more present in areas with middle to high density, middle income, more younger people, and lower percentages of couples with children. They are less present in areas with more recent immigrants and visible minorities. The most common features are related to greening and road safety, while water management was the least common even if it was the most important from a program standpoint. After controlling for alleysā morphology, the score of green alleys was significantly higher in alleys receiving a second phase of improvement. Private parking in backyards also strongly dictates the score of green alleys. Finally, boroughs are significant in explaining the distribution and score of green alleys, pointing to variations in coordination within the Cityās program. Our results help identify strategies to plan and design green infrastructure in an equitable and sustainable way.
Street trees are a common feature of urban nature, providing ecological, economic and social benefits. These public functions are highly dependent on specific design principles, including the composition and diversity of tree species within the urban forest. Consequently, it is important to understand the patterns and correlates of street tree distribution and diversity to assess benefit flows. This requires sampling across and within towns. This paper reports on an assessment of the distribution, composition and diversity of street trees between and within multiple South African towns, and ascertains the correlations between tree density and composition with social contexts. Randomly selected streets were sampled in the affluent, township and low cost housing suburbs of ten Eastern Cape towns. Sixty-nine out of 300 sampled transects had street trees, with 888 trees enumerated, spanning ninety-seven species. Alien tree species accounted for 71% of all the enumerated trees while indigenous trees species accounted for 12%. Tree density and composition were significantly lower in smaller towns and those marginalised during the previous racially-based political regime. Within towns, the poor areas had fewer street trees, with many streets having none. Collaboration and constant communication between the various government departments involved in suburb development is crucial to ensure a more rigorous incorporation of green infrastructure into the building and development plans of new housing developments.
The provision of shade through the urban tree canopy is critical to urban resilience, health, social equity and child-friendly cities in a warming world. Trees help to minimise heat islands and so cool cities. Trees are also important and efficient carbon-converters through photosynthesis and a growing body of research emphasises the human health and well-being outcomes of human-plant interactions. Recognising these benefits, greening strategies and practices have proliferated through both local government and āfriends ofā groups in many Australian suburbs. These include urban forest strategies, street tree policies, āAdopt-a-treeā programs and the more routine greening practices by community groups and households, nature strips and public reserves. Despite these initiatives, tree cover remains extremely uneven across metropolitan cities. Comparative analysis of vulnerability and tree cover by location shows that those who are most vulnerable to extreme heat events (Loughnan et al. 2012) often live in those parts of cities that are most poorly shaded (ISF 2014).
Many urban development processes, supported by land-use planning, negatively impact urban trees. Urban forest strategies are one approach local governments take to protect and increase urban trees. We evaluate connections between urban forest strategies and land-use planning to achieve tree cover on private property, through a review of 18 Australian local government strategies. We highlight the importance of state-level policies for local land-use planning, and conclude that if state-level land-use planning is to aid the protection and enhancement of urban trees, more active engagement with and explicit links to urban forest strategies at both local and state levels is needed.
We review the literature on the ecology and conservation of Australian urban birds and report the results of the first Australian study on the relationship between avifauna and habitat variation in exurbia, which is the low-density zone of development on the outer margins of a city. The Australian urban avifauna has synanthropes found widely elsewhere. It also has a large number of native species, some of which are globally threatened. The distribution of species in Australian urban areas relates better to their niche characteristics than their nativity or exoticness and better to very local variations in habitat type than to environmental variation at the landscape scale, which is often masked by the vegetation thickening associated with suburbanisation. In two exurban regions of Hobart, Tasmania, we sampled birds in unmodified wildland forest (native forests away from development), unmodified exurban forest (native forest on exurban properties), modified exurban forest (native forest on exurban properties and with the understorey removed), exurban gardens and exurban paddocks (cleared land). We tested the hypotheses that exurban habitats were different in bird species compositions from wildlands, that similarity in avifaunal assemblages within habitats increased with the degree of human interference and that, within dry open forests, the perforation (small clearances) and fragmentation associated with exurbanisation would be associated with populations of an aggressive small-bird-excluding edge species, the noisy miner Manorina melanocephala. The noisy miner occurred on old land clearance boundaries and not at all in recent forest perforations. In the absence of noisy miners, exurban bird species assemblages were organised by habitat, with the greatest internal consistency being within gardens. In both regions, paddocks had more heterogeneous bird assemblages than expected, and wildlands had identical species assemblages to unmodified exurban forests, but not to other habitat types. The mixture of habitats characteristic of exurbia may not necessarily be detrimental for avifaunal conservation as long as it includes substantial areas of undisturbed native vegetation, even though exurban development may be undesirable for other reasons. We conclude that it is the distinctiveness and high beta diversity of urban and exurban habitats that create opportunities for a wide variety of native and exotic bird species, that local manipulations and creations of urban and exurban habitat can substantially affect avifaunal conservation outcomes and that urban bird management should be a major component of many species recovery plans.
Uniformly control of the height of buildings owned by individuals to protect cultural heritage landscape causes social conflicts. Thus, it is necessary to introduce an indicator that can simultaneously evaluate the criteria for control of the height of buildings (CCBH) for urban development and cultural heritage landscape management. We developed 3D Visual Exposure (3DVE) as a useful indicator to review the validity of the CCBH around cultural heritage. By using the 3DVE, it was possible to calculate visibility and we succeeded in mapping the opportunity of view on 3D geospatial information and evaluating landscape variation with statistics through changing building heights around cultural heritage. We predict that the 3DVE presented in this study will have high utilization as an indicator for the cultural heritage landscape management.
Urban trees provide substantial public health and public environmental benefits. However, scholarly works suggest that urban trees may be disproportionately low in poor and minority urban communities, meaning that these communities are potentially being deprived of public environmental benefits, a form of environmental injustice. The evidence of this problem is not uniform however, and evidence of inequity varies in size and significance across studies. This variation in results suggests the need for a research synthesis and meta-analysis.We employed a systematic literature search to identify original studies which examined the relationship between urban forest cover and income (n = 61) and coded each effect size (n = 332). We used meta-analytic techniques to estimate the average (unconditional) relationship between urban forest cover and income and to estimate the impact that methodological choices, measurement, publication characteristics, and study site characteristics had on the magnitude of that relationship. We leveraged variation in study methodology to evaluate the extent to which results were sensitive to methodological choices often debated in the geographic and environmental justice literature but not yet evaluated in environmental amenities research.We found evidence of income-based inequity in urban forest cover (unconditional mean effect size = 0.098;. s.e.=. 0.017) that was robust across most measurement and methodological strategies in original studies and results did not differ systematically with study site characteristics. Studies that controlled for spatial autocorrelation, a violation of independent errors, found evidence of substantially less urban forest inequity; future research in this area should test and correct for spatial autocorrelation.
For cities to grow their urban forest canopy the formula appears rather straightforward: the right trees, plus the right conditions, plus the right care equals success. These simplified ātree chain of custodyā steps, however, represent activities within a complex value-chain in Canada. Given that there is heightened demand for urban tree planting as natural climate solutions become the norm, how can we prepare the value-chain to meet these demands? To answer this question, we outline the pathways by which trees presently go from nurseries into urban and peri-urban areas. Delineating the actors, roles, and present barriers to success exposes the complexity of the process and relationships in the value-chain, as there are distinct phases with multiple actor groups involved who influence, and are influenced, by one another. We explore the issues that pose prominent challenges to, as well as opportunities for, the value-chain. Emergent themes include communication, forecasting demand and timing, underpricing and undervaluing tree establishment, lack of awareness on the importance of soils, juvenile tree health, species selection, and gaps in evidence-based decision support tools. The touchstones of science and innovation, collaboration, and knowledge mobilization are pertinent for the value-chain in Canada to draw upon to navigate the future.
Pedestrian accessibility is a primary component of just and vital urban environments. Presence of usable sidewalks is the foundation of pedestrian accessibility, but their walkability depends on socioeconomic and contextual attributes. The mere presence of a sidewalk might not facilitate its usability or walkability. Use of sidewalks also depends on positive conditions of comfort and safety. In many climates, street trees contribute significantly to comfort and to perceptions of safety. Street trees also provide ecosystem services that benefit humans. Recent efforts to reduce non-point-source pollution through installation of green infrastructure provide opportunities to increase the presence of trees in pedestrian travel ways. Environmental justice considerations imply that accessibility, including sidewalk walkability, be fairly distributed to maximize individual, societal, and environmental benefits and to respond to limitations imposed by socioeconomic status (SES). Our main hypothesis is that SES is negatively correlated with the presence of street trees. This article draws on a microdetailed regional pedestrian data set to characterize the presence of street trees in a social equity context. We found that street trees are inequitably distributed in the study area. These findings could add power to requests for installation of street trees and green infrastructure in lower SES neighborhoods.
Spatial variation in plant diversity has been attributed to heterogeneity in resource availability for many ecosystems. However, urbanization has resulted in entire landscapes that are now occupied by plant communities wholly created by humans, in which diversity may reflect social, economic, and cultural influences in addition to those recognized by traditional ecological theory. Here we use data from a probability-based survey to explore the variation in plant diversity across a large metropolitan area using spatial statistical analyses that incorporate biotic, abiotic, and human variables. Our prediction for the city was that land use, along with distance from urban center, would replace the dominantly geomorphic controls on spatial variation in plant diversity in the surrounding undeveloped Sonoran desert. However, in addition to elevation and current and former land use, family income and housing age best explained the observed variation in plant diversity across the city. We conclude that a functional relationship, which we term the "luxury effect," may link human resource abundance (wealth) and plant diversity in urban ecosystems. This connection may be influenced by education, institutional control, and culture, and merits further study.
Because a large proportion of the urban forest grows on private property, it is necessary to have broad community support for urban forestry. As people from all over the world live in Canadian cities, it was hypothesized that people with different cultural backgrounds would have different perceptions of the urban forest. This hypothesis was tested by (1) researching different landscaping traditions; (2) interviewing members of four different communities; and (3) conducting vegetation inventories. Inventory and interview data provided a consistent picture of the four communities. The British community reacted the most positively to shade trees, they also expressed the greatest willingness to plant shade trees, had the most shade trees per square meter on their properties, and were the only group that liked naturalized parks (hiking paths). The Chinese community showed less yard maintenance than the other communities, and many of the Chinese indicated that they did not want to add trees to their property. The Chinese responded more favorably than the other groups to photographs depicting landscapes free of trees. Italian and Portuguese communities emphasized fruit trees and vegetable gardens, and responded negatively toward shade trees when these were in conflict with their gardens. These cultural differences are largely consistent with the traditional use of trees in British, Mediterranean and Chinese landscaping, and appear to be maintained among North American immigrant populations.
This research investigates the relationship between socioeconomic status and remotely sensed vegetation intensity in residential land in the Denver, Colorado metropolitan area. Land-cover data derived from aerial photography and nor-malized difference vegetation index data (NDVI) derived from Landsat ETM= imagery were integrated with U.S. Bureau of the Census tract-level data and analyzed using choropleth mapping and multivariate statistics. Association rule mining, a data mining technique, is used to explore nonlinear relationships among variables. Results indicate that higher vegetation intensity is associated with socioeconomic advantage in both sparsely populated, large lot suburban developments, as well as in older, urban neighborhoods. This pattern likely reflects residentsā ability to pay for the cost of maintaining high vegetation intensity, suburban lawn ecosystem vegetation in a semi-arid grassland environment. Additionally, residential choices may be limited by a home price structure that is closely related to the concentration of vegetation in the residential landscaping.
Urban forests and herbaceous open space play a vital role in the environmental and aesthetic āhealthā of cities, yet they are rarely identified in land-use inventories of urban areas. To provide information on urban forests and other vegetative land cover in Illinois cities, Landsat Thematic Mapper (TM) data from June 27, 1988, were classified for the Chicago metropolitan region (9,717 km^2). Ten land-cover classes were identified, including two types of forestland (occupying 5.8% of the total area), residential land with trees (14.6%) or without trees (7.8%), cropland (37.5%), two types of grassland (7.7%), urban with impervious surfaces (23.1%), water (1.6%), and miscellaneous vegetation (2.1%). Correlation analyses indicated that household income and household density are strongly related to land covers in the region, particularly those with tree cover and urbanized land. Population changes for 1980ā1985 and 1985ā2010 (projected) show a pattern of increasing density in the urbanized zone concurrent with continued urban sprawl, primarily into current cropland.
Residents of the largest metropolitan areas in the continental United States were surveyed about the benefits and problems of trees in urban areas. The public rated the social, environmental, and practical benefits of trees highly. The ability of trees to shade and cool surroundings was the highest-ranked benefit. Their potential to help people feel calmer was ranked second highest. Potential problems with trees were not considered to be reasons not to use trees. Practical problems, such as causing allergies, were bigger concerns than were financial issues. People who strongly agreed that trees were important to their quality of life rated the benefits of trees more highly than people who did not strongly agree. Those who strongly agreed and those who did not strongly agree ranked the benefits and problems similarly. Responses varied slightly based on demographic factors. For example, those who did not strongly agree that trees were important to life quality were more likely than expected to be 18 to 21 years old or to earn US$20,000 or less per year. The general public in urban areas, not just people who volunteer for tree programs, felt very positively toward trees in cities.
This article reports on the relationship between measures of farmers' conservation attitudes and motivations on the one hand, and their self-reported and observed management of windbreaks and woodlots on the other. The study was conducted on historic farms where tenureship is, on average, over four generations. A survey instrument assessed farmers' attitudes about farming, the benefits of using trees on farms, the aesthetics of the rural landscape, motivation and their self-reported conservation practices. An analysis of landscape patterns on respondents' farms was conducted by analysis of aerial photography. Findings suggest that a conventional, externally motivated approach to farming results in reduced use of farm woodlots and windbreaks. In contrast, an approach based upon aesthetic and intrinsic forces is predictive of increased use and maintenance of woodlots and windbreaks. It is suggested that the promotion of conservation practices on farms may benefit from subtle, non-economic interventions as well as from financial and regulatory approaches.
The 3-year Chicago Urban Forest Climate Project examined how trees affect these components of the regional urban ecosystem. The region`s tree cover has increased from a presettlement level of about 13 percent to nearly 20 percent today. There are an estimated 50.8 million trees in the region; 66 percent in good or excellent condition. The trees tend to be small; 77 percent less than 15 cm d.b.h. Street trees are only 10 percent of the city`s trees, but 24 percent of leaf surface area because they are typically larger than off-street trees. During 1991, the region`s trees removed an estimated 6,145 tons of air pollutants, providing air cleansing worth $9.2 million. Each year they sequester an estimated 315,800 metric tons of carbon and provide residential heating and cooling energy savings that, in turn, reduce carbon emissions from power plants by 12,600 tons annually. Increasing tree cover 10 percent or planting about three trees per building lot is estimated to save annual heating and cooling costs by $50 to $90 per dwelling unit once the trees mature. The net present value of services trees provide is estimated as $38 million, or $402 per planted tree. The present value of long-term benefits are more than twice the present value of costs.
How would inner-city residents respond to the incorporation of trees and grass in their neighborhoods? Law enforcement officials have argued that, in these settings, trees and other forms of vegetation increase fear. Tree density, tree placement, and levels of grass maintenance were manipulated in photo simulations of neighborhood outdoor space. One hundred residents of Chicago's Robert Taylor Homes living adjacent to the space rated the images with respect to preference and sense of safety. Although tree placement (subspaces created by trees, formality of arrangement) had little effect on sense of safety and no effect on preference, both tree density and grass maintenance had strong effects on preference and sense of safety (&eegr;2s from .49 to .89). Surprisingly, tree density and grass maintenance increased both preference and sense of safety. Results suggest that-contrary to some views-trees and grass maintenance can increase sense of safety in inner-city neighborhoods.
By 2050, 70% of the Earthās human population will live in urban areas. Urbanization can have a devastating impact on local
ecosystems, but these impacts vary across time and space. Identifying links between spatiotemporal change in urban ecosystems
and neighborhood socio-economics is crucial to management aimed at maintaining flora and fauna in urban areas. Here, we tracked
20 years of socio-economic change and 15 years of vegetation change in 32 residential neighborhoods in south-eastern Australia.
Regression models that explicitly accounted for a time lag between neighborhood socio-economic characteristics and vegetation
response explained more variation in vegetation cover than models that ignored the effects of time. Also, relationships between
vegetation and socio-economic factors were stronger in later years for the same neighborhoods suggesting the influence of
socio-economics is more readily identified in established neighborhoods. Socio-economic variables alone, or in combination
with biophysical variables, were better predictors of vegetation cover than only biophysical variables. Across space, vegetation
cover had a negative quadratic relationship with neighborhood housing density, peaking at mid-density values, and a positive
relationship with education level and immigration status (the percentage of residents with a non-Australian background). Over
time, housing density had a positive relationship with vegetation cover, reflecting an increase in vegetation as neighborhoods
develop. Our results highlight the need to understand temporal context when attempting to explain contemporary patterns in
vegetation cover and the increasing importance of socio-economic factors in influencing cover as neighborhoods become established.
S. Kaplan suggested that one outcome of mental fatigue may be an increased propensity for outbursts of anger and even violence. If so, contact with nature, which appears to mitigate mental fatigue, may reduce aggression and violence. This study investigated that possibility in a setting and population with relatively high rates of aggression: inner-city urban public housing residents. Levels of aggression were compared for 145 urban public housing residents randomly assigned to buildings with varying levels of nearby nature (trees and grass). Attentional functioning was assessed as an index of mental fatigue. Residents living in relatively barren buildings reported more aggression and violence than did their counterparts in greener buildings. Moreover, levels of mental fatigue were higher in barren buildings, and aggression accompanied mental fatigue. Tests for the proposed mechanism and for alternative mechanisms indicated that the relationship between nearby nature and aggression was fully mediated through attentional functioning.
Scientists and managers often use urban forest canopy cover as an indicator of for- est health. Furthermore, canopy cover is often the measure communities use to set tree planting goals. Little is known, however, about factors that contribute to varia- tion in canopy cover. We describe canopy cover in 60 urban areas in Central Indi- ana. We then propose and test a model that treats canopy cover as a function of eco- logical and geographic factors, urban form, socioeconomic factors, and a policy index. Urban areas are more likely to have more canopy cover if they are in counties with more canopy cover, have higher proportions of their populations with college degrees, have older housing stock, have both more land and land with slopes greater than 15%, and have denser stream networks. Population density, median household income, and planning and zoning or status as a Tree City are not corre- lated with urban canopy cover.
With effective planning and management, urban trees and forests will provide a wide range of important benefits to urbanites. These include a more pleasant, healthful, and comfortable environment to live, work, and play in, savings in the costs of providing a wide range of urban services, and substantial improvements in individual and community wellbeing. Urban forestry plans should begin with consideration of the contribution that trees and forests can make to people's needs. Planning and management efforts should focus on how the forest can best meet those needs. Past planning and management efforts have not been as effective as they might have been because planners and managers have underestimated the potential benefits that urban trees and forests can provide, and have not understood the planning and management efforts needed to provide those benefits, particularly the linkages between benefits and characteristics of the urban forest and its management.
This article investigates the role of urban political economy, private-public property relations, and race and ethnicity in the social production of Milwaukee's urban forest. By integrating urban-forest canopy-cover data from aerial photography, United States Census data, and qualitative data collected through in-depth interviews, this analysis suggests that there is an inequitable distribution of urban canopy cover within Milwaukee. Since urban trees positively affect quality of life, the spatially inequitable distribution of urban trees in relation to race and ethnicity is yet another instance of urban environmental inequality that deserves greater consideration in light of contemporary and dynamic property relations within capitalist societies.
Many city dwellers hold very strong personal ties ~esource management options. to urban trees andforests, with some attachments approaching Much of our initial work focused on predicting a spiritual involvement. Ties between people and trees are people's preferences for urban forest management associated with traditions, symbolism, and the need to "get invo1ved"at the local level to sustain or enhance the environment changes, for example, planting new trees along a for present and future generations. Urban forestry programs Street, increasing density of tree cover in a park, or that aim to improve quality of life in urban areas will be most designing changes in a landscape along a bicycle effective if urbanites learn about the basic biological needs of trail. As we conducted this work. however. it 2 - trees. At the same time managers and planners must learn about the many psychological, social, and cultural needs that became increasingly clearly to us that the values trees and forests fulfill for urbanites.
As a consequence of compacted soils, impervi- ous surfaces, heat irradiation, pollution, and other stresses, urban trees have an average expected service life of 10 to 25 years. Most public agency budgets for street tree replacement and maintenance are declining. Public tree managers need tools to prolong the service life of street tree populations while reducing the need for main- tenance activities (including pruning and pest manage- ment). Many jurisdictions rely on "approved tree" lists, but these often contain large numbers of species generally unavailable in a given area, and filters for diversity are seldom part of these documents. To avoid catastrophic losses and pest outbreaks associated with virtual monoc- ultures, the Maryland Department of Natural Resources has developed a methodology for assessing biodiversity in existing populations. An inventory is taken. The results of the inventory are broken down taxonomically by family, genus, and species; The results are then analyzed, with target levels established as follows: no more than 30% of any one family, 20% of one genus, or 10% of one species should be present. Based on the results of the assessment, recommendations are made as a tool for use in future re- placement contracts to bring about the desired species composition.
Urban areas in the conterminous United State doubled in size between 1969 and 1994, and currently cover 3.5 percent of the total land area and contain more than 75 percent of the US population. Urban areas contain approximately 3.8 billion trees with an average tree canopy cover of 27 percent. The extent and variation of urban forests across the 48 states are explored to help build a better understanding of this significant national resource. Urbanization and urban forests are likely to be a significant focus of forestry in the 21st century.
Examined whether the presence of nearby nature might lend urban public housing residents the psychological resources to grapple with the challenges facing them. More specifically, it examines whether natural elements in the public housing outdoor environmentātrees and grassācan assist in restoring the very psychological resources likely to be depleted in the struggle against poverty. In 145 urban public housing residents randomly assigned to buildings with and without nearby nature, attentional functioning and effectiveness in managing major life issues were compared. Residents living in buildings without nearby trees and grass reported more procrastination in facing their major issues and assessed their issues as more severe, less soluble, and more longstanding than did their counterparts living in greener surroundings. Mediation tests and extensive tests for possible confounds supported the attention restoration hypothesisāthat green space enhances residents' effectiveness by reducing mental fatigue. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
As highly managed ecosystems, urban areas should reflect the social characteristics of their managers, who are primarily residents.
Since landscape features develop over time, we hypothesize that present-day vegetation should also reflect social characteristics
of past residents. Using an urban-to-suburban watershed in the Baltimore Metropolitan Region, this paper examines the relationship
between demographics, housing characteristics, and lifestyle clusters from 1960 and 2000 with areas of high woody and herbaceous
vegetation cover in 1999. We find that 1960 demographics and age of housing are better predictors of high woody or tree coverage
in 1999 than demographics and housing characteristics from 2000. Key variables from 1960 are percent in professional occupations
(+), percent of pre-WWI housing (ā), percent of post-WWII housing (+), and population density (ā). Past and present demographic
and housing variables are poor predictors of high herbaceous cover in 1999. Lifestyle clusters for 2000 are very good predictors
of high herbaceous coverage in 1999, but lifestyle clusters from 1960 and 2000 are poor predictors of high woody vegetation
coverage. These findings suggest that herbaceous or grassy areas, typically lawns, are good reflections of contemporary lifestyle
characteristics of residents while neighborhoods with heavy tree canopies have largely inherited the preferred landscapes
of past residents and communities. Biological growth time scales of trees and woody vegetation means that such vegetation
may outlast the original inhabitants who designed, purchased, and planted them. The landscapes we see today are therefore
legacies of past consumption patterns.
KeywordsUrban landscapes-Social predictors-Legacies-Baltimore
Domestic (āprivateā) gardens constitute a substantial proportion of āgreen spaceā in urban areas and hence are of potential
significance for the maintenance of biodiversity in such areas. However, the size and nature of this resource and its associated
features are poorly known. In this study, we provide the first detailed audit, using domestic gardens in the city of Sheffield
as a model study system. Domestic gardens, the mean area of which was 151m2, cover approximately 33km2 or 23% of the predominantly urban area of the city. The smaller gardens contribute disproportionately to this total because,
although individually they add little, they are large in number. Conversely, the regions of the city with proportionately
more garden area contribute most to the total garden area of the city, although such regions are limited in number. Based
on the findings of a telephone based survey, 14.4% of dwellings with gardens were estimated to have ponds, 26% to have nest-boxes,
29% to have compost heaps, 48% to hold trees more than 3m tall, and 14% of dwellings were estimated to be home to one or
more cats. Whilst the absolute frequency of these features is low to moderate, by extrapolation they nonetheless yield estimates
for domestic gardens in Sheffield of a total of 25,200 ponds, 45,500 nest boxes, 50,750 compost heaps, 360,000 trees, and
a population of 52,000 domestic cats. These results are considered in the context of the role of gardens in urban areas as
habitats for wildlife and the implications for housing policy.
This paper is a review of research in Chicago that linked analyses of vegetation structure with forest functions and values. During 1991, the regions trees removed an estimated 5575 metric tons of air pollutants, providing air cleansing worth 9.2 million. Each year they sequester an estimated 315 800 metric tons of carbon. Increasing tree cover 10% or planting about three trees per building lot saves annual heating and cooling costs by an estimated 50 to 90 per dwelling unit because of increased shade, lower summertime air temperatures, and reduced neighborhood wind speeds once the trees mature. The net present value of the services trees provide is estimated as 402 per planted tree. The present value of long-term benefits is more than twice the present value of costs.
Domestic (Č8privateČ9) gardens constitute a substantial proportion of Č8green spaceČ9 in urban areas and hence are of potential significance for the maintenance of biodiversity in such areas. However, the size and nature of this resource and its associated features are poorly known. In this study, we provide the first detailed audit, using domestic gardens in the city of Sheffield as a model study system. Domestic gardens, the mean area of which was 151 m2, cover approximately 33 km2 or 23% of the predominantly urban area of the city. The smaller gardens contribute disproportionately to this total because, although individually they add little, they are large in number. Conversely, the regions of the city with proportionately more garden area contribute most to the total garden area of the city, although such regions are limited in number. Based on the findings of a telephone based survey, 14.4% of dwellings with gardens were estimated to have ponds, 26% to have nest-boxes, 29% to have compost heaps, 48% to hold trees more than 3 m tall, and 14% of dwellings were estimated to be home to one or more cats. Whilst the absolute frequency of these features is low to moderate, by extrapolation they nonetheless yield estimates for domestic gardens in Sheffield of a total of 25,200 ponds, 45,500 nest boxes, 50,750 compost heaps, 360,000 trees, and a population of 52,000 domestic cats. These results are considered in the context of the role of gardens in urban areas as habitats for wildlife and the implications for housing policy.
Four hundred Australians across the country shared their experiences of work, family, parenting and study for this book, creating a striking picture of Australian society as a new millennium begins. Meticulously researched, the volume presents a counter-argument to the regime of economic reform. Michael Pusey's sequel is as controversial as his best-selling Economic Rationalism in Canberra.
Residents of Melbourne, Australia (n = 192) were surveyed regarding their preferences for 36 trees presented in black-and-white photographs. The findings indicate preference for medium-sized trees with a globular or oval form. Foliage texture also arose as an important factor, with higher preference for trees with relatively broad or coarse foliage. While there was no overall preference for either native or introduced trees, categories derived statistically from preference ratings suggest this criterion may have been a consideration for many residents. Some findings could not be predicted from the published literature, which has largely been conducted in the Northern Hemisphere.
The status and prospects of urban trees in Hong Kong are evaluated with information gathered from questionnaires and a tree
survey. Planting and maintenance responsibilities fall to four government departments plus the private sector. Species composition
is unevenly distributed, with five popular species constituting over half of the trees sampled. The numbers of introduced and
cultivated trees far exceed those of native and voluntary ones. Species-selection without an evaluation programme is generally
conservative, but gradual shifts in preference are discernible. The multifarious physical constraints in both the above-ground and
subterranean environments that pose stringent limits on the number of potential planting sites and the growth of existing trees
are elaborated. Typhoons, which could periodically cause widespread damage, often regardless of species and location, could
only be partially mitigated by more comprehensive preventive measures. Pests and diseases which have not received detailed study
are apparently mild. Vandalism, which damages roughly 10-15% of trees planted, could be alleviated by planting more heavy
standard trees, but their supply is limited because of inadequate nursery space. The chronic shortage of tree staff aggravated by a
high job mobility, due mainly to comparatively low remuneration and poor promotion prospects, creates a bottleneck in the tree
programme. For the future, a city-wide tree survey together with a computer database are essential for efficient management,
maintenance and research. The existing, rather lax statutory control should be consolidated and tightened, with authority being
given to a single department which should be adequately supported by supervisory staff. Land could be zoned specifically, like
other land-uses, for tree planting, and this could be more generous and spatially more evenly distributed to allow penetration
of greenery into wider parts of the city. The potential in urban renewal areas where land could be released and reserved for planting
should be realized as far as possible. Overall, rising aspirations for better environmental quality could be achieved by a combination
of high-density vertical developments and strategically situated open spaces liberally adorned by landscape planting.
Amsterdamse Bos, Bois de Boulogne, Epping Forest, Grunewald, Zoniƫnwoud; throughout history, cities in Europe and elsewhere have developed close relationships with nearby woodland areas. In some cases, cities have even developed - and in some cases are promoting - a distinct 'forest identity'. This book introduces the rich heritage of these city forests as cultural landscapes, and shows that cities and forests can be mutually beneficial. Essential reading for students and researchers interested in urban sustainability and urban forestry, this book also has much wider appeal. For with city forests playing an increasingly important role in local government sustainability programs, it provides an important reference for those involved in urban planning and decision making, public affairs and administration, and even public health. From providers of livelihoods to healthy recreational environments, and from places of inspiration and learning to a source of conflict, the book presents examples of city forests from around the world. These cases clearly illustrate how the social and cultural development of towns and forests has often gone hand in hand. They also reveal how better understanding of city forests as distinct cultural and social phenomena can help to strengthen synergies both between cities and forests, and between urban society and nature.
The Million Trees LA initiative intends to improve Los Angeles's environment through planting and stewardship of 1 million trees. The purpose of this study was to measure Los Angeles's existing tree canopy cover (TCC), determine if space exists for 1 million additional trees, and estimate future benefits from the planting. High-resolution QuickBird remote sensing data, aerial photographs, and geographic information systems were used to classify land cover types, measure TCC, and identify potential tree planting sites. Benefits were forecast for planting of 1 million trees between 2006 and 2010, and their growth and mortality were projected until 2040. Two scenarios reflected low (17%) and high (56%) mortality rates. Numerical models were used with geographic data and tree size information for coastal and inland climate zones to calculate annual benefits and their monetary value. Los Angeles's existing TCC was 21%, and ranged from 7 to 37% by council district. There was potential to add 2.5 million additional trees to the existing population of approximately 10.8 million, but only 1.3 million of the potential tree sites are deemed realistic to plant. Benefits for the 1-million-tree planting for the 35-year period were $1.33 billion and $1.95 billion for the high- and low-mortality scenarios, respectively. Average annual benefits were $38 and $56 per tree planted. Eighty-one percent of total benefits were aesthetic/other, 8% were stormwater runoff reduction, 6% energy savings, 4% air quality improvement, and less than 1% atmospheric carbon reduction.
Relationships between attributes of the urban forest and the built environment and social characteristics of New Orleans, Louisiana are examined using several exploratory statistical techniques. In the relatively young field of urban forestry, much research has focused on the biophysical attributes and functional benefits of urban forests, including wildlife habitats, climatic amelioration, and noise abatement. Recognizing that urban forests are anthropogenic, the research reported here explores the urban forest in relation to urban land uses and social groups. Socioeconomic factors, as measured by census variables, are shown to be important determinants of the distribution of the urban forest as measured by tree canopy cover.
Three inventories were conducted to quantify Bangkok's green infrastructure for future planning and improvement in the context of a seasonal monsoonal dry climate. Total green space was quantified by extracting surface cover areas from remotely sensed data in a geographical information system (GIS) environment, and this information was used to designate suitable sites for future green spaces such as parks. Street trees were inventoried for species identification and size. Trees of heritage value were identified through a public awareness campaign, and then were subsequently surveyed for species identification, height and trunk diameter. GIS green space analysis showed that per capita park space was approximately 1.8m2, but a master plan proposed increasing per capita park area to 4m2 within 25 years. The increased park area will be largely in the form of lower cost, semi-naturalized tree parks. The inventoried street tree population, approximately 200,000, was skewed somewhat towards a monoculture, as 42% were the facultative evergreen Pterocarpus indicus Wild. By contrast, none of the other species exceeded 7% of the total. That most of the other species consisted of smaller trunk diameters than P. indicus, and therefore younger, suggests that Bangkok's street tree plantings are becoming more diverse. The heritage large tree inventory was dominated by evergreen tree species, particularly exceptionally large Ficus species, found largely on Buddhist temple grounds, followed by Albizia saman (Jacq.) Merr. The slower growing evergreen heritage species are worth careful appraisal and preservation because they are less likely to be commonly planted. Careful species selection balancing drought deciduous and dry evergreen species can achieve adaptation to the monsoonal dry season with diverse aesthetic quality in both Bangkok's street tree population and in its semi-naturalized tree parks.
Can enhancement of garden habitat for native birds have conservation benefits, or are garden bird assemblages determined by landscape and environmental characteristics? The relative roles of vegetation structure, floristics and other garden attributes, and environmental and landscape controls, on the abundance and richness of bird species in 214 back or front gardens in 10 suburbs of Hobart, Tasmania, Australia, are addressed to answer this question. Birds were counted in each garden and the resources they utilized noted. Vascular plant species and other attributes of the garden were noted, along with rainfall, altitude, distance from natural vegetation, distance from the city and garden size. Garden floristics and bird assemblages were ordinated, and garden groups characterized by particular assemblages of birds identified. General linear modelling was used to determine the combinations of independent variables that best predicted the richness of birds and the abundance of individual bird species and groups of species. The models for bird richness, bird species and groups of bird species were highly individualistic. Although native birds showed a preference for native plants, they also utilized many exotic plants. Exotic birds largely utilized exotic plants. Variation in garden characteristics does substantially affect the nature of garden bird assemblages in Hobart, with weaker environmental and landscape influences. The fact that gardens can be designed and managed to favour particular species and species assemblages gives gardeners a potentially substantial role in the conservation of urban native avifauna.
