In the endless democratization of our city we have brought social justice to streetscape design by making sure every tree is treated equally–even though no two trees are actually that alike since it is in their nature to be different (that’s how evolution works)– even trees of the same species will vary greatly from root size to height, from branching habit to trunk caliper.  But the Toronto Green Standards as applied to land development requires that every tree– no matter species, size, deciduous or evergreen—all follow the same rules.

Each tree is mandated to receive 30 cubic metres of soil, or if there are two or more they require 20 cubic metres per tree.  On the face of it seems like a rational requirement. Trees need soil for a long and healthy life, and we all want a beautiful and healthy urban forest.  But does the law know exactly how much soil makes a tree happy?  My practice has an urban designer and landscape architect has brought me to cities all over the world, and I have marveled at the differing approaches to a successful urban tree canopy.  In China 30 cubic metres of soil would support six trees, and properly designed, spaced and selected for their habit they would mature for decades in place.  In India, a tree is planted whether there is room or not.  In France, a tree is selected for its form and design integrity and the soil is provided as needed to make sure the design intent is met, and if there is not enough soil the tree is manicured to fit uncomplainingly in its place.  In Toronto, trees cannot be overplanted or underplanted.  They are checklist items without concern for possible variations in placement due to form, habit and design intent.  A cluster is not permitted, no matter how beautifully it might add to the urban experience—even if the trees would thrive and mature by design.


Jeff is a partner and urban designer, planner and principal landscape architect at Terraplan.

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