Biodiversity in our Urban Forests

By Jackie Hamilton

I have had the chance to talk to a LOT of people about trees. It’s really fun to get to see the variety of feelings out there, from seeing them as immortal beings that would live forever without humans to seeing them as annoying impediments to development or perfect lawns.
Most people though, fall somewhere in the middle ground of liking trees enough, but not really noticing them on a day to day basis. I do not fall into this group. To be a person that studies trees means that you will never be alone on the street or in the forest. I see familiar “faces” literally everywhere I go. On the occasion I see a tree I am unfamiliar with I stop to identify it (sometimes in the middle of a busy sidewalk – no shame). 

Who are you? Photo by Jackie Hamilton

​One of the (many) beauties of identifying trees is that you can take all the time you need, they aren’t going anywhere. There have been a couple trees that I was unsure of and had to re-visit in different seasons and bring fellow arborists to confer with. 

Meeting a tree somewhere in the age range of 2000 years. Photo by Jackie Hamilton

The downside of being someone that is interested in trees is you also see a lot of stress and mismanagement in our urban centres. Compared to us, trees are giant and ancient beings. It’s hard for people to understand but trees live in entirely different timescales than we do. Injuries and ailments like poor planting practices or root damage often take years to show in trees, at which point it’s often too late. It’s not initially clear that planting a tree in a 3 ft by 3 ft area surrounded by hard surfaces is a bad idea, but when you see those trees 3-5 years down the line they are often on death’s door.
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There is a lot of innovation that makes me excited about the future of trees in cities, including engineered soil beds and underground utilities. The movement toward these techniques is going to be gradual but so worth it for the long-term viability of our urban forests. 

Undergound utilities might have saved this tree from its haircut. Photo by Jackie Hamilton

​One of the best things we can do for our urban forest is to plan for as much biodiversity as possible. A biodiverse tree population is not only going to be able to support a high diversity of all other living things, but it is also a smart management move. With climate change and new introduced species, we really don’t know what tree species will be in our cities in 50-100 years, but we can be certain that by planting and maintaining a diversity of species we are reducing our losses. 

This beautiful oak lined street will look very different if there is a gypsy moth outbreak. Photo by Jackie Hamilton

Jackie Hamilton is obsessed with forests and all the benefits they provide us. Over the last 4 years she has been working toward more resilient and biodiverse forests in our urban and rural Ontario landscapes. Prior to this, Jackie worked as an environmental scientist. She also serves as the lead of the Fundraising and Membership Working Group on the board of the Emerging Leaders for Biodiversity.
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