At 52 hectares, about half the size of High Park, Crothers' Woods, a small Carolinian Forest at the foot of the Leaside Bridge, is an ecological rarity in these parts.
Signage erected at Beechwood Wetlands nearby warns walkers and birders to tread softly. "Areas like the Lower Don Valley that have been heavily disturbed by human activity are particularly susceptible to the effects of invasive non-native species."
But despite being declared an ecologically sensitive area more than a decade ago, Crothers is being sliced into mucky ribbons by trail bike enthusiasts who think nothing of carting in chainsaws and cutting down mature trees to build ramps for their daredevil jumps.
Illegally constructed stunts and jumps on the steep forest hillsides of Crothers were torn down a few years ago, but the degradation, including the excavation of huge ditches for jumps in the flats between Crothers and Beechwood Wetlands, has continued at a breakneck pace.
Large turnouts of 30-something male riders, a fixture at public consultations in recent years, show little concern for preserving this rare forest we're lucky to have this far north.
The Planning Partnership (TPP), the consulting group coordinating and authoring a new management plan for the area, seems intent on maintaining a system of bike trails through Crothers.
As if to justify the cyclists' presence, one TPP member observed at a November 2006 consultation that "volunteer user groups [read the pro-off-road International Mountain Bicycling Association, or IMBA] have removed over 3 tons of garbage from the valley in recent years."
Indeed, TPP has received extensive input from IMBA.
Durham region IMBA rep Jason Murray says the group wants to "keep the riding experience the same - a good and fun experience." At the same time, he admits that "overuse is what has caused the spaghetti effect" on muddy trails.
Friends of the Don East points out that mountain biking is banned in other Toronto ravines. But planners, instead of protecting the area outright, are hell-bent on making the trails multi-use. Urban forestry supervisor Garth Armour was the only city staffer at the recent public consultation to say that "jumping and skills facilities should be elsewhere."
"A continuity of environment," says Gavin Miller of the Toronto and Region Conservation Authority, "and of our Natural Heritage Strategy are the overall TRCA thrust."
But there's little talk of sustaining the unique wildflower meadows, reserving areas for wildlife or looking at the Don Valley as a whole corridor system.
Miller points out that "TPP's [draft] plan results in a net reduction in [bike] trail kilometres."
Crothers' interior is intersected by 10 kilometres of natural surface trails, densely in its steepest third. The consultants propose to close only 1.8 kilometres of duplicate trails on these highest-sensitivity slopes.
Sean Wheldrake, bicycle promotions coordinator, says city cycling ambassadors, who are paid city staff, will be dispatched to Crothers to reduce conflict and educate trail users.
But the ambassadors, while versed in trail etiquette, are not trained in biota (flora and fauna) recognition, wildlife protection or restoration.
Friends of the Don East has produced a paper noting that mountain biking is banned in Glendon Forest and Rouge Park and confined to trails by fencing in Sherwood Park.
"Ecological integrity must be the guiding principle of any strategy," says the Friends report. "Without this, the forest will not survive."
Stephen Smith, a forester and certified arborist, argues that "there are plenty of areas already ravaged in the city, plenty of brown lands that could easily be converted to allow stunt riders.
"Neither dog walkers nor bikers are a passive use, and it only takes a few to ruin it for the rest."