Diminutive and slow-growing, tundra vegetation is found in cold, dry alpine and arctic regions where trees cannot fully develop. Alpine tundra circumscribes high mountain slopes in many parts of the world, while arctic tundra circles the Earth at high northern latitudes, edged by the Arctic Ocean to the north and boreal forests to the south. Here, the tundra’s vast plain of distinctive vegetation is underlain by a thick layer of permafrost. Arctic tundra is frozen and snow-covered much of the year, but is brimming with life during brief northern summers. Barry Lopez notes, “Arctic tundra can open suddenly . . . when any intimacy with it is sought.” Witness the detail of sedges, mosses, lichens, and miniature ﬂowers. The infestations of summer insects. The dozens of bird species that migrate to the tundra for nesting season. Caribou, polar bear, wolverine, muskox, grizzly. Cairns, graves, tent rings, carved wood: isolated and subtle signs that humans have moved across its reach.