The benefits of urban forests, defined as all natural and planted trees in or near an urban area, are well known. However, research finds that there is inequitable access to urban forests and green spaces. Urban tree canopy tends to be higher in higher-income neighbourhoods with fewer minority residents. Unequal access of low-income and racialized Canadians to urban forests results in unequal access to their benefits, creating an environmental injustice.  

With the government of Canada committing to plant 2 billion trees (2BT) over the next 10 years, the expansion of urban forests and urban parks is a political priority. With about 82% of Canadians living in urban areas, designing cities to be more livable through greater urban forest cover is an important priority. 

Source: This is your brain on trees: Why is urban nature so good for our minds, and what happens when a pandemic isolates us from it?

Proposals for how to make urban living more equitable are numerous and diverse. In February 2021, Dr. Cecil Konijnendijk, Professor of Urban Forestry at the University of British Columbia (UBC), started promoting the 3-30-300 rule for urban forestry as a means of creating greener and healthier cities. Based on current evidence on the benefits of urban trees and green spaces, the rule calls for every resident to be able to see at least 3 decent-sized trees from their home, live in neighbourhoods with at least 30% tree canopy cover, and live no more than 300 meters from the nearest public green space. Obviously, such a rule needs nuancing and adaptation to local situations, but it also represents a powerful way of communicating the benefits of urban forests and green spaces to politicians, experts from other sectors, and citizens.

Nature Canada sat down with Cecil to understand his motivation for developing this framework and to better understand how Canadian municipalities could leverage the federal commitment to plant 2 billion trees in ways that create equitable access to urban spaces for urban residents. Cecil is also the Director of the Nature-Based Solutions Institute in Spain. Cecil is passionate about using trees and nature to develop better cities and always stresses the importance of building meaningful relationships between people and places. He has advised international organizations such as the Food Agricultural Organization of the United Nations, as well as national and local governments in more than 30 countries. 

Q: Thank you very much for taking the time to talk to us today. Why do urban forests matter? 

Urban trees and urban green spaces provide a lot of benefits. There are three main benefits. The first is to human health. One of the most important benefits of urban forests is the interception and reduction of air pollution. Secondly, is the potential of urban forests to support climate change adaptation. The increase in heat and heat-related health problems is especially prevalent in cities, where the urban heat island effect increases the impact of heatwaves. Third, trees, especially the mature ones, perform a key role in terrestrial ecosystems. Trees are critically important, especially in urban areas, as they provide food and habitat for birds, invertebrates, mammals, and plants. Improving and maintaining biodiversity is necessary for a sustainable city. So, the added value is that people can come into contact with this biodiversity. So, trees provide multiple benefits simultaneously and are relatively cheaper compared to technical infrastructure.

Q: The 3-30-300 rule is gaining a lot of attention. Why 3-30-300 and what was your motivation?

I have often been asked by cities: what should we have as canopy cover? What should be the nearest distance to green spaces? I have always been very careful in responding because I want to make sure my proposals are evidence-based. But sometimes you also need to have a simple message that people can remember. Many of us working in this field are familiar with Frank Santamour’s 10-20-30 rule for ensuring species diversity in the urban forest. The rule states that no tree species should make up more than 10% of a municipality’s urban forest, no genus should have a share larger than 20%, and no single family should make up more than 30% of the urban forest. Although this rule has been debated, it has become widely known and adopted, most likely having a positive effect on urban forest structure and diversity. The 10-20-30 rule, however, does not have a specific focus on the benefits provided by urban forests. 

Given the current climate, biodiversity and public health urgencies, as well as a range of other challenges, I felt it would be useful to introduce a guiding principle for urban forest programmes, and city greening across the world, that ensures that all residents have access to trees and green space and the benefits these provide. As a consultant who works a lot with politicians and decision-makers, I started thinking about how I could package the evidence in a way that people would remember.

Regarding the formula, the European Regional Office of the World Health Organization recommends a maximum distance of 300 metres to the nearest green space (of at least 1 hectare). A safe 5-minute walk or 10-minute stroll from their homes is often mentioned. 

As for the 30% canopy cover, research in Australia shows that 30% is the minimum cut-off for health benefits. Cities can strive for higher canopy covers whenever possible. But where it is difficult for trees to grow and thrive the target should be at least 30% vegetation. Recent research also finds that visible greenery is extremely important for mental health and we have seen that during COVID. The Danish municipality of Frederik has a tree policy that calls for every citizen to see at least one tree from their house. So, I thought to myself, why one tree? We need some diversity and because we already had 300 and 30, I decided to go for 3 trees. So, there is evidence behind 300-30, though may be a bit less for the 3 trees.

Q: What has the impact been so far? Which cities are adopting the rule? Specifically, are there any Canadian cities/municipalities/districts etc.?

In Canada, the District of Saanich, BC formally adopted the rule in June 2021. Several other UK local councils, e.g. Stonehouse, have mentioned the rule in their urban strategies. The ruling Green Party in the Dutch city of Utrecht has proposed implementing the rule. Also, the Nordic Council of Ministers have asked me to integrate the 3-30-300 rule into their policy guidance for urban green space. In general, all these initiatives use the rule to promote the importance of trees and green spaces for climate, health and biodiversity benefits.

Q: In Canada, the federal government has committed to planting 2 billion trees over the next 10 years. With over 80% of Canadians living in urban areas, how can this commitment be leveraged to ensure optimal benefits for climate, biodiversity and human well-being?

It’s great to see many governments and even celebrities committing to planting thousands of trees. While these commitments are important, what is more important is what we are going to do with these trees. We need to ensure that planted trees are well catered for and protected. We need to work with municipalities and communities to ensure that tree planting is meaningful. That implies planting trees in the right places and ensuring there is a management plan. Some places will not be the right places. In order to succeed we also need capacity building and training on the management of urban trees. 

Q: An important aspect of building meaningful relationships between people and places is ensuring there is equitable access to urban forests and green spaces for every urban resident irrespective of their race, socio-economic status etc. How can the 3-30-300 rule enable us to achieve such outcomes in Canada?

Urban trees and greenspaces are inequitably distributed across many cities such as Vancouver. Black, Indigenous communities and people of colour tend to have less access to urban forests and urban green spaces. Applying the 3-30-300 rule will improve and expand the local urban forest in many cities, and promote health, wellbeing, and resilience. For example, in New York, neighbourhoods with lower access to urban trees and green spaces are being targeted for tree planting. This means diverting funds for developing places such as Manhattan to these neighbourhoods. Cities cannot have a general tree canopy cover target. It needs to be a neighbourhood target so that everyone can have equal access to urban forests and green spaces. 

Conclusion 

Providing equal access to green spaces could provide significant climate and biodiversity benefits. It can also improve mental health and reduce inequities faced by lower-income neighbourhoods and racialized communities. The pandemic has given us an opportunity to rethink how we live together, including how we live with each other and our urban forests. 

The time to start this conversation with your municipality and decision-makers is now.

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