To the casual observer, Toronto’s ravines are blazingly beautiful right now, but walking the trails with a forestry expert reveals that beauty is only skin deep.The trees with flaming yellow leaves in the Park Drive ravine off Mount Pleasant Rd. are invasive Norway maples; the leafy shrubs with stalks that look like bamboo are rapacious Japanese knotweed and the forest floor is virtually barren when it should be covered in seedlings and saplings.“This is just a hill of destruction,” says forestry expert Eric Davies, sweeping his arm across a slope of the ravine, beneath Glen Road Bridge in Rosedale.The slope is littered with trees toppled by soil erosion, disease and in the case of the ash trees, a beetle native to Asia called the emerald ash borer.The invasive Norway maples taking over the ravine inhibit undergrowth, so there is little to tether soil to the slope and erosion is exposing the roots of native trees — oaks and sugar maples — to freezing in winter.“When you look at that slope, there is nothing on there — there are no herbaceous plants, there’s no shrubs, there are no seedlings,” says Davies.“The soil — it’s getting hammered from all different sides.”Davies is a University of Toronto forest ecology PhD student and one of the co-authors of the Toronto Ravine Revitalization Study: 1977-2017, released last week. It found that over the past 40 years, the biodiversity and ecological health of Toronto’s ravines has declined to a critical level and is now likely on the edge of ecological collapse. It’s still possible to save them, says Davies, but action needs to be taken soon. Toronto has essentially been carved out of a vast ravine system, which still covers 11,000 hectares of land (27,000 acres), accounting for 17 per cent of the city.Walking through a ravine with Davies brings the quiet struggle within it glaringly to life.As he points to the problems on the slope ...
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