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Canadian Urbanism Uncovered

Tree Tuesday: Big old bitternut

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Every Tuesday, Todd Irvine of Local Enhancement and Appreciation of Forests (LEAF) will post a stop from the Toronto Tree Tours, a collaborative project of LEAF and the Toronto Public Space Committee. The Toronto Tree Tours offers walking tours in neighbourhoods across the city as well as virtual tours on its web site. The aim is to introduce Torontonians to the individual trees in their neighbourhood while telling stories of our city’s ecological and cultural history.

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Trinity Bellwoods and neighbourhood tour: Stop 6

At the corner of the tennis courts to the southeast of the park, standing watch over the people playing below is the park’s most elderly resident. This giant bitternut hickory (Carya cordiformis) is believed to be as much as 250 years old, likely a remnant of the mixed hardwood forest that once looked over the edge of the now filled-in ravine. Bitternuts are native to the northern United States and the southern reaches of Ontario and Quebec and are the most abundant and widespread of Canadian hickories. The wood is used for producing the smoke that gives bacon and ham its hickory-smoked flavour. As the name implies, the tree’s nuts are not edible.

This tree’s bark is showing its age. It is pitted and scarred due to the hundreds of years it has stood in one place. When a tree’s bark is damaged, it seals off the wound but does not heal it by replacing the cells as human skin does, which leads to marks that linger for decades. The rounded growths on the trunk of this tree are called burls. They are a localized overgrowth of cells that cause small knots that disfigure the tree. They emanate from the tree’s cambium, a thin layer under the bark where new cells are produced, enabling the tree to put on girth. The specific cause of burls is unknown, but it is thought microorganisms, insects, or environmental stress may trigger the swellings. Carvers prize burls because they have unique grains and can be easily shaped into bowls and sculptures.

Of the many experiences this tree has lived through, including fires, development, drought, and storms, perhaps the greatest challenge was overcoming the damage that was caused when the tennis courts were built atop its roots mere inches from the base of its aged trunk.

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