Nebraska National Forest: The Sandhills Underneath the Pines

Drive out of the Halsey plantation pines and the landscape changes within a mile. The hills roll up in long gentle swells, the grass running golden to the horizon in every direction without a tree in sight. This is what the Nebraska Sandhills actually are: the largest sand dune complex in the Western Hemisphere, roughly twenty thousand square miles of stabilized dunes, held in place by a continuous carpet of native grasses whose roots go down six, eight, ten feet into the sand.

The Sandhills formed roughly eight thousand to twelve thousand years ago, when the climate was drier and the Great Plains winds built enormous dunes out of glacial outwash sediment. When the climate shifted wetter, the grasses moved in and pinned the dunes in place. The stabilization is fragile. Where the sod breaks, whether from drought or overgrazing or heavy machinery, the sand can start moving again. Sandhills ranchers understand this in their bones. Overgrazing is not an abstract environmental concern here. It is the difference between a working ranch and a blowing sandpile.

The Sandhills aquifer is among the most significant in North America. The porous sand and the grasses above it together form a vast recharge zone for the Ogallala Aquifer, the underground freshwater body that underlies eight states and irrigates roughly a third of American groundwater-based agriculture. The lakes scattered through the Sandhills, more than seven hundred of them, are windows into that aquifer. Their water levels track the Ogallala. When the Ogallala drops, they drop.

Samuel McKelvie National Forest, named for a Nebraska governor, occupies a corner of the Sandhills near Valentine. It is managed less as a timber forest than as grassland and wildlife habitat, because the Sandhills were never forest country. The designation is a bureaucratic category applied to land the land does not entirely recognize.