The tree the world is arguing over is a Fitzroya cupressoides, the alerce, and the park takes its name from it. These conifers grow with almost inhuman slowness, adding rings so thin that millennia can pass before the trunk thickens to the width of a car. The Alerce Milenario is more than 60 meters tall with a trunk over four meters across, but its real measurement is in time. To stand beside it is to stand beside something that has watched the entire arc of recorded human history pass while it simply, patiently grew. A short trail leads visitors to it through old-growth forest thick with lichen and dripping ferns, where other ancient alerces tower in the same green twilight.

This mountainous coast did something extraordinary during the last Ice Age: it survived. When glaciers ground across much of southern Chile during the Quaternary, the Cordillera Pelada served as a refuge, a pocket of life that the ice never fully claimed. Later it weathered the region's volcanic upheavals. The result is the Valdivian temperate rainforest, one of the planet's rarest forest types, where species found nowhere else cling to a narrow ribbon of the Chilean Coast Range. The park guards the Chaihuín river basin and the community that depends on it, protecting both an ancient ecosystem and the people whose lives are bound to its water.

The Cordillera Pelada means the Bald Mountains, and the name is a scar. Between roughly 1750 and 1943, as Spaniards, Chileans, and European settlers pushed into the land between Valdivia and the Maullín River, they set fire to the alerce woods again and again. The burns stripped whole slopes bare, leaving the blackened patches that gave these mountains their name. Fire had always touched this forest, sparked earlier by lightning and by the indigenous people who lived here, but the colonial era turned occasional flame into systematic clearing. Trees that had taken three thousand years to grow could vanish in an afternoon, a loss measured not in board-feet but in lost centuries.

Beneath the canopy moves a cast of creatures shaped for this specific place. The güiña, or kodkod, slips through the brush as one of the smallest wild cats in the Americas, while pumas range the higher ground. The pudú, a deer barely knee-high, picks through the undergrowth, and the crow-sized Magellanic woodpecker hammers at dead trunks, its scarlet head flashing in the gloom. Even the plants hunt here: two species of carnivorous flora, the sundew and the bog violet, trap insects in a forest where the soil gives up little. Carved from a public-private effort that united state reserves with land donated by The Nature Conservancy, the park became a national park in 2010 and now ranks among Chile's priority sites for biodiversity.