North of Mayfield Road in Caledon, 102 endangered trees are standing on land owned by the Ministry of Transportation of Ontario (MTO). Within the next few weeks, the ministry’s contractor plans to cut them down to extend Highway 410. Once the chainsaws start, there is no undoing the damage.

This treed land isn’t a park or conservation area, and doesn’t have an official name. It is simply a tract of forest on MTO-owned land, unremarkable on a map and irreplaceable on the ground. We’re calling it Butternut Grove, for the endangered trees that make it worth fighting for.

Highway 410 currently jogs west near its northern end and merges with Highway 10. Now the MTO wants to reroute Highway 410 so that it proceeds directly north at the Mayfield Road exit while extending it just over 5 kilometres to the proposed Highway 413 — the fantasy highway whose design is years from being finalized and a project that has yet to receive federal permits. In the process of pushing through this unneeded spur, MTO will wreak havoc on a forest containing both endangered and old-growth tree species.

This is happening despite the Province of Ontario and the Town of Caledon currently investing north of $30 million on the existing Highway 410 to Hurontario upgrade project with a scheduled completion date in 2027. These highway improvements are being cost-shared between Ontario and the municipality: $15.2 million will come from the Ontario Municipal Housing Infrastructure Program (MHIP-HECS), covering 50 per cent of the total road project cost.

So picture this, a new four-lane highway project being proposed (no cost being disclosed) just as the Province of Ontario invests $30 million in upgrading the Highway 410 to Hurontario road less than two kilometres away?

But also picture the ecological damage that the Province of Ontario doesn’t want you to know about: 102 endangered Butternut and Black Ash trees, standing in a forest located north of Mayfield Road in Caledon. Both species are listed as endangered in Ontario, and Butternut is also listed federally under the Species at Risk Act. The butternut canker has devastated one species, and the emerald ash borer is killing the other. Species are designated as endangered when they become rare enough that every survivor, and every habitat they live in, matters.

These trees also can’t be protected by saving only a few individual trees. MTO’s own field protocols call for a root zone of roughly 21 metres around each Butternut and nine metres around each Black Ash. A highway, however, will destroy the trees and the ground that keeps these trees alive.

Here is what makes me furious. MTO examined three alternative alignments for the Highway 410 extension, then chose the most environmentally destructive of the three. That was no accident. MTO’s own Environmental Impact Assessment Report explains why:

“The alternative maintains development for both sides of Highway 410 including along Heart Lake Road (desired by the Town).” (p.3-43)

That is the smoking gun. The goal is to maximize developable land on both sides of Highway 410. This is a real estate decision masquerading as an environmentally sound decision, and endangered trees will pay the price.

The damage won’t stop when this grove is cut down. Butternut Grove is home to a tributary and wetlands that serve as the headwaters to Etobicoke Creek. Water, wildlife and living roots tie this landscape together. Clear-cut the Grove and you introduce more road salt, tire-origin heavy metals, microplastics, engine oil and transmission fluid – all from the highway, and pollute the health of a place that families across the region know and love.

The protection rules are also shifting under our feet. The Endangered Species Act was repealed earlier this year by the weaker Species Conservation Act, and MTO admits the province hasn’t released updated survey guidance about if or how to protect endangered trees. Protections are absent while the woodlot destruction is being scheduled.

Time is running out. Here’s what you can do now:

Contact Ontario’s Minister of Transportation and the Town of Caledon Council to demand an alignment that avoids Butternut Grove and the habitat of its endangered trees. Ask why $30 million in taxpayer dollars is being invested on the 410 to Hurontario upgrade if the Highway 410 extension is being built.

Demand a halt. No clearing should begin until both the alternatives and the development rationale behind the chosen route have been publicly reviewed.

Spread the word. Share this post with friends, neighbours and anyone who enjoys the Etobicoke Creek watershed, including Heart Lake. Public attention is the one thing that can stop the chainsaws. Endangered means there are not enough left to lose. A straighter road and more developable land don’t change that.

Join Environmental Defence’s campaign against Highway 413, so that this isn’t the last grove we save.

Tell your MPP and the Minister of Transportation that Highway 413 should be cancelled.