Exploring the field of urban forestry

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Over 50 per cent of the world’s population now lives in urban areas and, according to the World Health Organization, that number will continue to grow.

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Away from green fields, mountains and grasslands, because of high density building and massive networks of paved surfaces, urban neighbourhoods can be anywhere from two-to-four Celsius warmer than surrounding rural settings.

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In order to make urban locations more livable, cooler in summer, more people-friendly and more accommodating to wildlife with the inclusion of adequate green spaces, urban forestry has become the focus of many cities around the world.

I was delighted to speak with Dr. Andrew Almas, assistant professor of teaching at the Faculty of Forestry at the University of B.C. Almas is a leading urban forestry authority, and it was great to get his perspective on just where this field of study is going.

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I was surprised to learn that while there are courses on urban forestry available at other schools and universities across Canada, UBC offers the only bachelor’s degree program.

When I asked about the evolution of the concept in Canada, Almas said it really began at the University of Toronto in the 1960s. By the early ‘90s, and into the new century, there were conferences being held in Canada where the visualization of the context of urban forestry continued to be refined and broadened.

Forestry is a provincial mandate. But Almas believes both forestry and urban forestry need to be looked at from a national perspective. Each province has a different approach to forests and forest fire management, which he thinks needs a national focus, especially when we’re facing more extreme weather patterns.

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Urban forestry encompasses so many aspects of making urban areas more environmentally friendly; from helping to mitigate summer heat and creating a more livable environment for people, to recreating lost wildlife and pollinator habitats. We are all aware of the many health benefits of green spaces in cities and, as populations grow, they become even more invaluable.

Almas pointed out some of the many challenges facing this incredibly important discipline. In North America, the average lifespan of trees, including those in smaller cities, can be between 18 to 23 years. In Vancouver, with all the realities of water restrictions, and more extreme weather conditions, that drops down to about eight years.

This brings up two critical issues: finding the right trees for today’s realities, and the proper planting and care of these trees.

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Almas said part of the solution lies in making greater use of native trees. The challenge is finding nurseries that grow the right selection of specimen-sized varieties for successful planting.

He also pointed out that in nature, as the climate changes, there is a natural migration of native plants that adapt to the warmer temperatures. Assisted natural migration of species means planting more heat- and drought-tolerant varieties and hoping they will also withstand our more extreme winter weather.

Getting juvenile trees to survive and thrive in urban areas is also a challenge because appropriate watering is an issue. Almas is a strong advocate of grey water usage. Unfortunately, the massive amounts of grey water we produce is wasted. It gets talked about, but very little is being done to actually put it to use in our cities.

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In the meantime, collecting rainwater is one of the most important things we can do to supplement water supplies for irrigation during hot summer months.

Real estate developments can also be detrimental to urban forestry as contractors remove so many mature trees to make way for new construction. It’s the larger trees we really need, according to Almas. He strongly believes in the preservation of these larger, existing trees and doing whatever we can to help them survive. They provide canopy cover for shading and help retain moisture in our soils, all while pulling in carbon dioxide, producing oxygen and cooling temperatures by moving moisture through the air. In many cases, they’re also more easily adaptable to our changing climates.

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Almas recognizes that part of future success is proper messaging on how important all aspects of urban forestry are to our well-being. It’s not only about getting citizens to encourage decision-makers to prioritize the greening of our cities, but also to challenge everyone to become stewards of plants and trees in their neighbourhoods by assisting with watering and care in times of drought.

The future of urban forestry is also about small incremental changes; planting the best new climate adaptable trees, prioritizing efficient use of grey water and ensuring better survival of juvenile trees to increase their lifespans.

Despite the many challenges, urban forestry has become an essential factor in making our cities livable.

For further information, and suggestions for resilient trees, visit: News.ubc.ca. 

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