A modern ark

ALONG THE BANKS of the Apalachicola river, near the border between Florida and Georgia, lives a rare tree called a stinking cedar. Once common, Torreya taxifolia seems to have got stuck in this tiny pocket as the continent warmed after the last ice age. It cannot migrate northward because the surrounding soils are too poor. Attacked by fungi, just a few hundred stinking cedars remain along the river. Rising temperatures now threaten to kill them off entirely.

Spying a looming extinction, a group of people is engaged in a kind of ecological vigilantism. The self-styled “Torreya Guardians” collect thousands of seeds a year and plant them in likely places across the eastern United States. Stinking cedar turns out to thrive in North Carolina. The Torreya Guardians are now trying to plant it in colder states like Ohio and Michigan as well. By the time the trees are fully grown, they reason, temperatures might be ideal there.