Seeing the forest for the trails

The forested ravines that wind through Toronto are one of our city's most valuable resources. They filter the air, absorb rain and stormwater, and prevent erosion. They're also home to many species of birds, mammals, and plants, and are the last remnants of the forest that blanketed this region prior to European settlement.

Sadly, the threats to our ravines are numerous. Exotic plant species choke out native vegetation. Pollution shortens the lifespan of trees, and outbreaks of invasive insects eat away at the canopy. As Toronto increases in density, buildings and pavement close in on all sides.

An increasingly pressing problem is by all appearances much less ominous: people on bikes. Adventurous mountain bikers are creating what the City's forestry staff call spontaneous social paths, networks of trails that criss-cross through wooded areas. Unplanned, these paths are destructive to the natural ecosystems that cyclists enjoy.

Crothers' Woods, located in the lower Don ravine, is an epicenter of the outbreak of such paths. Its canopy, over 60 feet above the forest floor, is comprised of a diverse mix of trees including sugar maple, oak, beech, and bitternut, many over a hundred years old. The understory and surrounding meadows include rare plants with playful names like Poke Milkweed and Sweet Joe-Pye Weed, leading the Toronto and Region Conservation Authority to deem it an environmentally significant area.

Located on a remote, undulating slope with mature trees and rolling streams, the trails in Crothers' Woods are touted on biking websites read across North America. But as the site grows in popularity, so too does the pressure on its ecology. Bike tires pack down the soil and crush tender understory plants. Most damaging are "fall line" trails that go straight down a hill. Rainwater flows down these barren strips during a storm, eroding soil into the river, causing deep ruts to form on the trail, which exposes tree roots, leaving them to dry out and die. To avoid the ruts, bikers ride on the sides of paths, causing them to widen. In time, a trail that began as two feet wide can grow to over 20.

Garth Armour, Supervisor of Natural Environment and Community Programs for the City of Toronto, has been looking for a solution to this problem for over a decade. To some, the obvious answer would be to fence the bikers out. But, speaking from experience, Armour says, "There would be holes in that fence within 24 hours." As it was clear that no plan to improve the health of the woodlot would succeed without the buy-in of the cycling community, Armour and his colleagues enlisted the help of the International Mountain Biking Association (IMBA), an advocacy organization whose mission is to preserve riding opportunities for cyclists through education and the construction of sustainable trails.

In the spring of 2004, over 40 volunteers participated in a weekend trail-building workshop organised in Crothers' Woods. On the Friday evening, IMBA representatives and City staff educated the cyclists on the need for sustainable trails. Saturday morning, they toured the site to identify problem areas and devise techniques to ameliorate the damage. For the remainder of the weekend the volunteers set about improving the site. The worst of the fall line trails were closed off by wooden fencing, replaced with paths that follow the natural contours of the topography. To discourage bikers from reopening the closed trails, they planted trees and spread branches and leaves. Where trails met creeks, resulting in muddy rutted pools, they built small bridges of piled stones that allow water to pass through undisturbed while bikes travel over top.

To maintain this momentum, IMBA trained over a dozen volunteer trail builders to lead workshops and provide the ongoing stewardship trails require. The City is doing its part by organizing similar events each spring and fall. Jason Murray, one of those trained as a trail builder, acknowledges that not every rider is excited about the push towards more managed trails. "The mountain-biking community may have to give stuff up in the short term," he says. "But if everyone is bargaining in good faith, the benefits will last much longer because the trails are not going to deteriorate."

Armour and his colleagues have created a forum where environmentalists, cycling advocates, trail runners, hikers, and even dog-walkers (one of the newest threats to the woods) can discuss each other's concerns. In the late fall of 2006, they held an open house to gather input on the development of a management plan for Crothers' Woods. The results were positive. As John Routh, a community member of the Task Force to Bring Back the Don, explains, "you can't force these groups out of the valley until the City provides an alternative, because there is nowhere else for them to go." In the interim, everyone is going to have to continue to work together so that the natural environment and the people who enjoy it for recreation can coexist and, ideally, sustain one another.