White Pine Hollow: Iowa's Ancient Forest

Iowa is not known for old-growth forest. Settlers plowed and logged nearly everything within reach of an axe. But in a deep canyon in Dubuque County, steep terrain and dolomitic rock made the logging too difficult, and a stand of ancient white pine survived.

White Pine Hollow, a nine-hundred-forty-four-acre state forest near New Vienna that contains a state preserve, protects one of Iowa's last old-growth white pine stands, relics from a colder postglacial climate when pines ranged much farther south. Local advocates pushed for protection as early as nineteen twenty-two. The area was designated a state forest in nineteen thirty-four, named a National Natural Landmark in nineteen sixty-seven, and listed as a state preserve in nineteen sixty-eight.

The canyon's geology, part of the Driftless Area, includes deep sinkholes, winding rock bluffs, and a microclimate cool enough to sustain species otherwise found much farther north.