White spruce trees are expanding into the Arctic tundra with stunning speed, with potentially serious consequences both for the region and the world.
IN THE SUMMER of 2019, Roman Dial and his friend Brad Meiklejohn hired a single-engine bush plane out of Kotzebue, on the northwest coast of Alaska. Even those wings could only get them within a five-day hike of where they wanted to be: deep in the tundra, where Dial had noticed peculiar shadows showing up in satellite images.