Social Correlates of Vegetation Patterns in the GTA

Project Summary

This project seeks to document and analyze the impact of neighborhood condition, household characteristics, community groups, urban form, and muncipal policy on vegetation patterns within the Greater Toronto Area. In doing so, we are addressing the following objectives:

1. Examine different aspects of urban form and neighbourhood socioeconomic characteristics as they relate to urban vegetation patterns.

2. Examine the impact of relevant municipal policy and community groups on current urban vegetation patterns.

3. Explore the link between the small-scale decisions made by residents and broader vegetation patterns.

4. Understand the motivations and barrier associated with household actions related to urban forests.

5. Examine not only tree canopy cover, but also tree density and species richness as measure of urban forest conditions.

Recent Publications

(* indicates a student)

Conway, T.M., *T. Shakeel, and *J. Attallha. 2011. Community groups and urban forestry activity: Drivers of uneven canopy cover? Landscape and Urban Planning 101 (4): 321-329.

Conway, T.M. 2009. Local environmental impact of alternative forms of residential development. Environment and Planning B: Planning and Design 36: 927-943.

Conway, T.M. and *L. Urbani. 2007. Variations in municipal urban forestry policies: a case study of Toronto, Canada. Urban Forestry and Urban Greening 6(3): 181-192.

Conway, T.M. and J. Hackworth. 2007. Urban pattern and land cover variation in the greater Toronto area. The Canadian Geographer 51(1): 43-57.

Conway, T.M. 2007. Impervious surface as an indicator of pH and specific conductance in the urbanizing coastal zone of New Jersey, USA. Journal of Environmental Management 85(2): 308-316.

Student Research

Tooba Shakeel (M.Sc., supervisor) Residents as drivers of urban forest patterns, ongoing since 2011.

Kirstin Bourne (M.Sc., supervisor) The biogeography of Peel’s urban forest: patterns and correlates of species diversity, completed 2011.

Elizabeth Bang (undergraduate thesis) Level of Support for Tree and Garden-Related Policies in the City of Mississauga, AY 2011-2012.

Kyle Brannen (undergraduate thesis) Home-Based Edible Gardening In Mississauga, AY 2011-2012.

Funding

“Seeing the forest through the people: households' relationship with urban trees”, 12-17, $220,800 from Social Sciences and Humanities Research Council of Canada (SSHRC). PI T.M. Conway, Collaborators J. McKay and L. Nelson

"New Urbanism as Green Urbanism: Exploring Socio-Ecological Relationships in Toronto and Calgary", 09-12, $74,097 from Social Sciences and Humanities Research Council of Canada (SSHRC). PI T.M. Conway, Collaborator J. McKay.

"Urbanization and Ecological Pattern in Toronto, Montreal, and Vancouver", 06-09, $44,874 from SSHRC. Sole investigator.

Context

Urban Ecosystems, Inequalities, and Trees

Within the urban ecosystem framework, the configuration and composition of urban forests is conceptualized as a result of complex interactions between biophysical and social factors. While biophysical conditions are particularly important in understanding differences in urban forests between cities around the globe, when examining urban tree patterns within a single metropolitan area, McDonnell and Pickett (1990) argue that built, social, and policy factors are more influential. The last decade has seen several studies highlighting the relationship between built form, municipal policy and vegetation conditions, suggesting factors like available planting space, road density, age and type of housing stock, and policies promoting planting and protection explain some of the variation in urban forest cover (Conway and Bourne in review; Conway and Hackworth 2007; Conway and Urbani 2007; Fung and Sui 2000; Grove et al. 2006; Heynen and Lindsay 2003; Hope et al. 2003; Landry and Chakraborty 2009; Smith et al. 2005; Stone 2004).

Drawing on political ecology, recent work has explored the role of neighbourhood socioeconomic status in relation to urban tree cover. Across North America, household income and other measures of neighbourhood wealth are consistently shown to be positively related to the extent of neighbourhood vegetation cover (Emmanuel 1997; Heynen and Lindsay 2003; Iverson and Cook 2000; Landry and Chakraborty 2009; Martin et al. 2004; Morales et al. 1976; Pedlowski et al. 2002; Talarchek 1990). Additional socioeconomic factors often found to be correlated with measures of urban vegetation at the neighbourhood-scale include average level of education (Heynen and Lindsay 2003; Landry and Chakraborty 2009; Talarchek 1990), ethnic and racial composition (Heynen et al. 2006; Landry and Chakraborty 2009; Troy et al. 2007), percent of owner-occupied dwellings (Heynen et al. 2006), and overall occupancy rates (Emmanuel 1997; Heynen et al. 2006). These correlations suggest that the benefits of urban forests are unevenly distributed among different socioeconomic groups within cities, supporting the inequality hypothesis that has been documented for a variety of environmental amenities and hazards within the environmental justice literature (c.g. Grineski et al. 2007; Landry and Chakraborty 2009). Specifically, neighbourhoods with lower socioeconomic status have less tree cover, thus receive fewer benefits from the urban forest (Heynen et al. 2006; Landry and Chakraborty 2009; Pedlowski et al. 2002).

The specific mechanisms driving these socioeconomic-based neighbourhood inequalities are unclear. For example, several authors have suggested that because people desire trees (Heynen and Lindsay 2003), which is evident through higher values for residential property with trees (Anderson and Cordell 1988; Donovan and Butry 2010; Payton et al. 2008), a positive feedback loop exists between canopy cover and property values (Heynen 2006). Thus, wealthier neighbourhoods have more trees, while declining neighbourhoods tend to lose canopy cover. Heynen (2006) documented this cycle in Indianapolis, where canopy cover declined alongside household incomes, while Emmanuel (1997) found that a decrease in urban ‘greenness’ was correlated with various measures of urban decay in Detroit. In addition, wealthier neighbourhoods may have greater political influence, which can lead to increased tree planting along public rights-of-ways in such neighbourhoods (Heynen 2006; Landry and Chakraborty 2009). However, others have shown that a desire for greater tree cover is not uniform among wealthy households (Grove et al. 2006), but that differences in preference often exist between cultural groups (Fraser and Kenney 2000) and by ‘lifestyle group’ (Grove et al. 2006).

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While neighbourhood-level studies have highlighted inequalities in urban forest distribution and related benefits, finer-scale work is needed to fully understand the impact of individual household decisions and the underlying mechanisms at play, and can potentially identify pathways to reduce existing inequalities.

Residential Landscaping: Preferences and Behaviour

A growing literature is examining people’s preferences for specific residential landscaping styles (Larsen and Harlan 2006; Larson et al. 2009; Nassauer et al. 2009), including but not limited to presence of trees. This research is often based on participants rating a series of photographs showing the same house but with different landscaping, following Kaplan (1985). Research has suggested that environmental attitude, cultural norms, aesthetics, and demographics all influence landscaping preferences (Yabiku et al. 2008). Interestingly, Nassauer et al. (2009) found that neighbourhood norms had more of an influence than cultural norms on residential landscaping preference, which is in line with studies that found front yard landscaping types tend to be spatially clustered (Henderson et al. 1998; Zmyslony and Gagnon 1998; for exception see Kirkpatrick et al. 2009). While allowing for comparisons between styles, this research approach does not necessarily situate preferences within the framework of households’ own properties, thus overlooking constraints like physical space limitations, as well as motivations behind actual landscaping decisions (for exception see Larsen and Harlan 2006). Additionally, many of the recent studies focusing on residential landscaping preference occurred in the unique desert environment of Phoenix, and are not focused specifically on trees.

Until the last few years, there has been little research examining households’ landscaping behaviour (Larson et al. 2009). However, recent research has begun to explore the chemical and water inputs associated with landscaping practices, often with emphasis on lawn grass care (Cook et al. in press). Generally, wealth and education-level are the best predictors of input use (Larson et al. 2011; Robbins et al. 2001; Zhou et al. 2008; Zhou et al. 2009). Additional studies have also explored the relationship between herbaceous (i.e. non-woody) gardens and household demographics, with emphasis on species selection, overall diversity and gardeners’ goals and behaviour (Bhatti 2006; Bhatti and Church 2000; Doody et al. 2010; Head and Muir 2006; Kendal et al. 2010; Marco et al. 2008; Marco et al. 2010; Zagorski et al 2004). While these studies have begun to illuminate household landscaping behaviour, and the broader ecological effects of such activities, tree planting and care has not been the focus to date.