Trac­ing the fam­ily tree

An ef­fort to cat­a­logue Toronto’s old­est, most ma­jes­tic trees is a key step to­ward pre­serv­ing the city’s canopy.


Toronto’s big­gest and tallest trees are rare sur­vivors, the last bas­tions of a former land­scape. En­gi­neer­ing mar­vels, they cool our cities and clean our air. The old­est, most ma­jes­tic ones over­whelm with their beauty. By th­ese mea­sures, th­ese gi­ants be­long in a mu­seum. Yet de­spite their eco­log­i­cal and his­tor­i­cal sig­nif­i­cance, there is cur­rently no over­ar­ch­ing plan to pro­tect — or even to cat­a­logue —Toronto’s very large, old trees.

“Imag­ine if we treated his­tor­i­cal ar­ti­facts the way we treat th­ese trees,” says Eric Davies, an ecol­o­gist who is iden­ti­fy­ing and map­ping sig­nif­i­cant na­tive trees in Toronto’s ravines.

“In most of the city, we don’t know where they are, we don’t know how big they all are, or if they are healthy.”

“Th­ese trees are the old­est, largest liv­ing things in Toronto,” adds Davies, who is pur­su­ing his PhD at the Uni­ver­sity of Toronto’s Fac­ulty of Forestry.

“We should be pro­tect­ing them with the same kind of pas­sion that we give to great works of art.”

With­out a base­line tally of the city’s big, old trees, there is no way to judge the full im­pact when one dies or is cut down.

As Davies points out, it’s hard to pro­tect some­thing when you don’t know how many you have in the first place.

In hopes of spurring a larger move­ment to find and map the city’s big­gest, old­est trees, Davies has shared his data set of sig­nif­i­cant ravine trees with the Star.

He knows the 905 trees he has mapped so far — more than half of which mea­sure al­most one me­tre in di­am­e­ter — are just a small sam­ple of the big and old spec­i­mens among Toronto’s 10.2 mil­lion trees. Still, he says, his in­ven­tory is a nec­es­sary start.

Toronto has long touted it­self as a treefilled city with its park­lands, shady streets and vast net­work of forested ravines.

Cur­rent es­ti­mates sug­gest the ur­ban for­est canopy cov­ers about 28 per cent of the city, and a 2017 study by the Mass­a­chu­setts In­sti­tute of Tech­nol­ogy, in col­lab­o­ra­tion with the World Eco­nomic Fo­rum, ranked Toronto fifth in the

world for its canopy cover — ahead of Los An­ge­les, New York, Lon­don and Paris.

Around the world, many cities are aim­ing for 40 per cent canopy cover to max­i­mize the ben­e­fits of trees.

Toronto has also pledged to reach that am­bi­tious goal and, ac­cord­ing to city bud­get doc­u­ments, aims to plant 120,000 a year on pub­lic prop­erty and in city-owned road al­lowances.

The city’s Strate­gic For­est Man­age­ment Plan says that won’t be enough; some 300,000 trees need to be planted on pri­vate prop­erty every year to reach the canopy cover tar­get.

While plant­ing new trees is a crit­i­cal com­po­nent of Toronto’s tree strat­egy, tree ad­vo­cates say more needs to be done to pro­tect and care for the city’s big­gest trees.

Not just for their beauty and ties to our past, but be­cause the big­ger the tree, the big­ger the ben­e­fits — from clean­ing and cool­ing the air to soak­ing up flood­wa­ters and in­creas­ing prop­erty val­ues.

Ac­cord­ing to the city’s own cal­cu­la­tions, a tree with a trunk di­am­e­ter greater than 75 cen­time­tres (29 inches) can cap­ture10 times more pol­lu­tion and can store up to 90 times more car­bon than a 15-cen­time­tre tree.

Cur­rently, just 14 per cent of Toronto’s trees, whether grow­ing in back­yards, park­lands or neigh­bour­hood streets, have trunk di­am­e­ters larger than 30 cen­time­tres (about a foot), and a much smaller per­cent­age of this are ex­cep­tion­ally large trees. The av­er­age Toronto tree is roughly 16 cen­time­tres in di­am­e­ter.

Philip van Wasse­naer, a con­sult­ing ar- borist at Mis­sis­sauga’s Ur­ban For­est In­no­va­tions Inc., says too many large trees are un­nec­es­sar­ily cut down or overly pruned be­cause too few peo­ple have the knowl­edge or skills to prop­erly care for them.

Com­bine that with the in­creas­ing pres­sures of ur­ban de­vel­op­ment, dis­ease, drought, storms and in­sects, and it’s no won­der, van Wasse­naer says, that Toronto is los­ing more and more of its large, valu­able trees.

“Some of th­ese trees are hun­dreds of years old. What con­founds me is that we, who should be stew­ards of th­ese trees, can so eas­ily de­cide to get rid of them, and gen­er­a­tions of his­tory in­stantly dis­ap­pears.”

In Toronto, a per­mit is re­quired to cut down a pri­vately owned tree with a trunk di­am­e­ter of 30 cen­time­tres or more. Fur­ther by­laws pro­tect street trees and trees grow­ing in parks and ravines.

As­mall per­cent­age of Toronto’s big, old tree pop­u­la­tion is pro­tected un­der the pri­vate tree by­law, which says trees with her­itage recog­ni­tion, as de­ter­mined by Forests On­tario or through the On­tario Her­itage Act, can­not be in­jured or re­moved with­out a city coun­cil vote.

Ac­cord­ing to a city spokesper­son, there are cur­rently 41trees with her­itage des­ig­na­tion in Toronto, as well as three groves and three rem­nant forests.

Coun­cil­lor Glenn De Baere­maeker (Ward 38, Scar­bor­ough Cen­tre, and not run­ning in the up­com­ing elec­tion) has been the city’s tree ad­vo­cate.

He agrees Toronto’s big­gest, old­est trees should be ac­counted for in a bi­o­log­i­cal in­ven­tory, ide­ally one that

“A 250- or 300-year-old oak tree takes a long, long, long time to get that big. We need to keep them, value them, pro­tect them.” SANDY SMITH UNI­VER­SITY OF TORONTO

would take stock of both the gi­ant trees and the health of the forests in which they grow.

De Baere­maeker says city coun­cil has pre­vented the re­moval of her­itage trees “99 per cent of the time,” but adds the city and cit­i­zens need to be bet­ter stew­ards of what he calls “cathe­dral trees,” which he likens to great works of art.

“When peo­ple buy a house with a 100year-old tree in the back­yard, they have to know they are tak­ing on a Mona Lisa tree,” he says.

“There has to be more aware­ness, ed­u­ca­tion and even a moral im­per­a­tive from cit­i­zens that if you do own a Mona Lisa tree, you have to care for it and pro­tect it.”

Ear­lier in 2018, a mas­sive 250-year-old red oak grow­ing in a North York back- yard prompted heated city­wide dis­cus­sions about who is re­spon­si­ble for pre­serv­ing Toronto’s old­est, largest trees.

A re­al­tor rep­re­sent­ing own­ers of the bun­ga­low on Coral Gable Dr. said the city needed to pur­chase the prop­erty or the tree, which was threat­en­ing the struc­tural in­tegrity of the house, would be chopped down.

In July, coun­cil ap­proved a plan to be­gin ne­go­ti­a­tions with the home­own­ers to ac­quire the prop­erty, with pro­vi­sions the red oak is deemed healthy and at least half of the funds used to pur­chase the house come from pri­vate do­na­tions.

Since 1985, New York City has main­tained a her­itage tree registry of ma­ture trees that are un­usual in size or shape or have a his­tor­i­cal tie to the city.

Res­i­dents can, through the NYC Parks Stew­ard­ship Pro­gram, vol­un­teer to be tree stew­ards to help with their care.

In the U.K., vol­un­teers add old and sig­nif­i­cant trees to The An­cient Tree In­ven­tory, which has more than150,000 trees in its data set.

And just down the road from Toronto, the City of Mis­sis­sauga has, since 2007, sup­ported a Sig­nif­i­cant Tree Pro­gram, which al­lows res­i­dents to nom­i­nate any city-owned tree for recog­ni­tion. So far, 50 trees have been rec­og­nized as a way to pro­mote their com­mu­nity value.

Sandy Smith, pro­fes­sor of forestry at the Uni­ver­sity of Toronto, wants peo­ple to start look­ing at big old trees in the same way we look at big old build­ings.

“Toronto’s Old City Hall is only still there be­cause some­one deemed it valu­able,” she says.

“We need to do the same with our old and im­por­tant trees. It seems ob­vi­ous to say, but a 250- or 300-year-old oak tree takes a long, long, long time to get that big. We need to keep them, value them, pro­tect them.” The Star wants to hear about the most sig­nif­i­cant trees in your neigh­bour­hood. Send an email to mogilvie@thes­ with a photo of your tree and the fol­low­ing in­for­ma­tion: Tree type (species), trunk cir­cum­fer­ence (mea­sured at chest height), lo­ca­tion of the tree and 150word ex­pla­na­tion for why this tree de­serves recog­ni­tion. We may share your sub­mis­sion with read­ers in the Toronto Star and on thes­


“Th­ese trees are the old­est, largest liv­ing things in Toronto,” says Eric Davies, a U of T re­searcher who is map­ping the old­est and big­gest trees in the city’s ravines.

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