Evaluating the meaning and distribution of ‘Tree Equity’ in Surrey: An interdisciplinary approach

Having access to trees reduces respiratory illness and improves mental health and well-being (Pataki et al 2021). Tress also provide protection from climate extremes such as flooding and heatwaves (Leets et al 2022). Regrettably, trees are unevenly distributed amongst urban populations. Wealthier communities tend to have greater access to trees than those more socially disadvantaged (Din and Krisko 2022). Ethnicity and education have also been identified as factors that underpin access to trees. However, as argued by Riley and Gardiner (2020) inequity is not universal but ‘context dependent’ and therefore greater attention needs to be paid to local issues to understand the nature of inequity in particular areas.

Investigating tree equity can be problematic due to the fact that the meanings and measures of tree equity are varied. Some approaches use tree canopy data derived from Google alongside air pollution and air temperature data, health statistics and socio-demographic data to calculate how fairly trees are distributed amongst urban populations (Devlin 2023). Others use Lidar, remote sensing, aerial imagery or local authority tree surveys. Species type, height, quality and age might also impact the benefits of canopy cover. Moreover the location of industrial sites, traffic corridors or other sources of pollution will undermine the benefits of canopy cover (Skyberg 2023). As a result there is little consensus on which variables or techniques best capture the phenomenon. 

Research that explores how tree inequity is redressed, focuses mainly on the role of planning authorities and the manner in which environmental goals, residential and commercial development needs, and funding are balanced. Given the benefits of trees for carbon sequestration tree planting now forms part of many Climate Action Plans (Angelo et al 2022). However, the availability for space to plant trees is also unevenly distributed and can be lacking in disadvantaged neighbourhoods. This means that greening initiatives may cause further inequity (Danford et al 2015). The role of conservation and community groups who lobby for, and engage in, greening initiatives has also been identified as a driver of tree equity (Leets et al 2022). Collaboration between local authorities and community groups has been found to be effective for implementing initiatives although the way in which success or benefits are measured varies from project to project, making evaluation and good practice difficult to identify (Garrison 2021).

This project will address some of the issues outlined above notably the uncertainty over variables and methods, the need for more consideration of local contexts, and the need to measure outcomes of local authority/community partnerships and iniatives. Moreover, the project addresses a fundamental gap in the literature, namely the dearth of research in the UK context.

Working with Surrey Wildlife Trust (SWT) and their tree equity research agenda (SWT 2023), this project will:

(1) Evaluate meanings and measures of tree equity as understood from the perspective of different stakeholders. This will involve a review of the environmental and sociological literature, and consultation with policy makers, environmental organisations, community groups and members of the public.

(2) Examine if tree equity features, and could feature, in local authority and national planning policy and legislation, looking at environmental, climate change and social justice policy and biodiversity targets. This will involve a policy review and consultation with policy makers.

(3) Design and implement a methodology to map and measure tree equity in Surrey. This will involve a consideration of the tree equity literature, focussing particularly on methodologies, and a consideration of the contextual issues as they pertain to Surrey. The goal here is to identify appropriate variables which enable us to better understand how tree equity/inequality works and the groups/areas that could benefit from better equity.

(4) Design and evaluate three community engagement projects that encourage public participatifon in tree equity initiatives. This will draw on principles of effective community engagement, including co-design and co-delivery with community partners (Webb et al 2019). This will also involve a consideration of underserved communities and/or groups who might not normally engage with nature or who might be underserved by nature.

The successful candidate will work on at least one of these strands of research. The project will be supervised by an interdisciplinary team which includes academics from Geography/GIS, Environmental Science, Sociology and Design.