Fred Dunn emerges from his winter tent.

He is a little old man in the woods, a fairy-tale leprechaun with a magical wee abode tucked behind the trees, a beard of red flecked with grey, hands gnarled, blue eyes ablaze.

He speaks in rhyme, scattering bits of wisdom in the lines of poetry that pour from his mouth.

When he stops talking, as he only reluctantly does, he runs. He runs like religion, sprinting up hills with an 80-pound timber hoisted onto a shoulder, peeling off dirty wool socks and rolling up his trousers in sub-zero temperatures to gallop barefoot in the snow.

Fred Dunn is a storybook character in real time, a modern-age hermit abiding in an urban forest. For the past dozen years, he has dwelled in a scrubby downtown ravine surrounded by the bustle of the biggest city in the country.

In his patch of woods in Toronto's Don River ravine is the ceaseless din of cars and trucks hurtling along the Don Valley Parkway, which cuts through the city like a spine. Subway trains thunder above the Bloor Street Viaduct overhead with deafening regularity.

In the winter, the branches bare, Fred's sprawl of artifacts salvaged from city garbage cans is visible from the road. In glorious summer, he is hidden from the sight of passing drivers oblivious to the population of tenants in the forest year-round.

Toronto is a city of ravines, its streets and bridges built over the centuries around the rivers and creeks that snake from beyond the city's northern reaches down to feed Lake Ontario.

Some of its busiest roads slice through the ravines. Its oldest and grandest homes overlook them.

In 1795, Upper Canada's first lieutenant-governor, John Graves Simcoe, and his wife, Elizabeth, built a summer house called Castle Frank on the crest of the valley, its lush view of leaves and winding river sketched in Mrs. Simcoe's diaries. Toronto's oldest standing home, Drumsnab, was built in 1830 on the valley's bluff nearby.

In time, the forest on the banks of the Don gave way to farms and factories -- brickworks, flour mills and sawmills, a paper plant spewing chemicals into pristine waters. Now, the industries have shut down, and all that remains of the Castle Frank name since the house burned to the ground more than a century ago is a dingy subway station.

Behind the trees of the ravines is a parallel universe, a secret world of people drawn to the isolation of the forest. To happen upon their shrouded tents is to step through the looking glass into another place entirely.

They regard the woods as their home, making them a breed apart from the flocks of homeless people huddled on street corners and crammed into shelters.

From Toronto's northern limits down to where the Don River spills into Lake Ontario, and in ravines spreading to the east and west, all these people have staked a claim to public land, living under an uneasy, unspoken truce with the authorities.

Their tents, their precarious perches under bridges are undisturbed by works crews and parks employees who tend to turn a blind eye when crossing their paths. Still, they seldom light campfires, mindful that a skein of smoke above the treetops would give police an excuse to evict them.

Who are these lost souls living outside in the woods, more like the native people who first inhabited the river valleys than the civilized society that they have inexplicably abandoned? Where are they from? And how can they choose a life outdoors in such an affluent city and bitter climate?

It is as though the tug of the ravine is an unshakable curse, with the people living among the trees sentenced to life as the ultimate outcasts, hiding behind summer leaves, soaking in the chill of fall rain, freezing in winter snow.