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On Patricia Avenue in Kitchissippi, next to the street where I live, stood an old-growth bur oak. It grew up in a forest fragment that predated confederation, and was connected through ancestry to the ancient oak forests that for 9,000 years graced this stretch of the Ottawa River.

In recent decades, the shade of the tree hosted an annual street party for the residents of Patricia. June 15, 2022 began the laborious task of dismembering the tree. It was irreparably damaged by the “derecho,” the violent May 21, 2022 storm that devastated southern Ontario and parts of Quebec. A deep, vertical fissure down the trunk created a serious risk to neighbouring houses and people. The tree could not be saved.

Residents gathered the day before removal began to thank the tree for all it has given to the creatures around it. A similar sized oak in the neighbourhood, a metre in diameter, was professionally dated as being a sapling in 1857. The Party Tree was of the same vintage.

For residents, the demise of the tree is an emotional blow, but also a significant economic loss. A tree of this size and shape conserves 1,000s of kilowatt hours per year in cooling and heating energy costs, filters hundreds of thousands of litres of storm water every year, removes 10s of kg per year of air pollutants, and safely stores massive amounts of carbon. An urban heat island map shows this street as a cool oasis, with surface temperatures on July 18, 2019 when the data was collected of 21 C. Streets nearby were heated to 32 C. While it may seem counter-intuitive at the moment, as our summers become increasingly hot, and people turn up the air conditioning, tree canopy will become critical to the stability of our electrical grid.

Something else has been lost with the Party Tree, less evident to the naked eye. Ontario’s Heritage Act distinguishes between built heritage (like the Chateau Laurier) and natural heritage. Historical records show that the Party Tree was part of a small forest before Patricia and nearby streets were opened in the late 1940s for housing. Home builders deliberately left this and some other nearby old growth trees in place.

The Party Tree is also connected to earlier generations of trees growing along the Ottawa River. Pierre Chevalier de Troyes, a French explorer, described in his 1686 journal “the oak forest” between Chaudière Falls and Deschênes Rapids (French for “some oaks”). An Algonquin name for a site at Aylmer across the river, Michiming (“place where the oaks grow”), is an older human connection.

The natural history is even deeper. An unbroken chain of ancestors connects the Party Tree to the original forests that grew up here as glaciers retreated more than 9,000 years ago. The genes of this particular tree have tasted this soil for thousands of years, and adapted to a millennium of wind storms, mini-droughts, and periodic flooding of the river banks. Deep time is held in its branches, leaves and acorns.

As we pivot from storm recovery to rebuilding a resilient city, we must embrace urban forests and heritage trees, not ban them from our streets and backyards. Shade and transpiration save more lives than they threaten.

Still, how we rebuild matters, including location and species selection. Heritage trees offer a guide post to what has endured, and what we can still draw on. Near native species -- trees from immediately south of us where average temperatures are higher -- also offer options to safeguard a shaded future.

The reason native species are important should be evident. Plants are the foundation of ecosystems. In our Eco zone, trees historically make up the bulk of the plant biomass. If the vast majority of those trees are not native or near-native species, the rest of the native ecosystem cannot survive.

Cities across Ontario and the country have established natural heritage bylaws to protect and propagate individual trees and groups of trees with heritage value, but not Ottawa. Other jurisdictions have also taken stronger stands than Ottawa on protecting and promoting native and near native species in both public and private spaces. For example, tree nurseries and landscaping companies receive no firm direction from the City regarding tree and shrub species, or origin of seed sources. Non-native, invasive species such as the Norway maple, Japanese lilac, Amur maple and European linden continue to be offered to unwitting residents. Even the LRT contractors are allowed to plant non-native species.

In our backyard, we have five tiny saplings from acorns collected two years ago from the Party Tree, which we will offer to the neighbours nearby. It is time the City did its part by making heritage trees and native biodiversity a priority in city building.

Daniel Buckles

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