Lost Forest Research Natural Area, Protected research forest in Lake County, Oregon.

Lost Forest Research Natural Area is a protected forest in Lake County, Oregon, where ponderosa pines grow in an isolated desert environment at about 4,400 feet elevation. The forest spans roughly 8,960 acres and is managed as a research area to study how these trees adapt to extremely dry conditions.

The Lost Forest is a remnant of an ancient ponderosa pine forest that covered much of central Oregon thousands of years ago, when the climate was cooler and wetter. Over the past 3,200 years the surface water of the Christmas Lake Basin dried up, leaving the stand isolated by 40 miles of arid desert. The Bureau of Land Management later designated it a Research Natural Area to protect the old-growth pines.

The name comes from its isolation: the stand lies 40 miles from the nearest contiguous pine forest. The Bureau of Land Management manages the area, and 4,153 acres are classified as prime old-growth forest. Visitors can see a western juniper 68 feet tall, the largest known in Oregon.

The forest sits about 65 miles southeast of Bend and is reachable by desert roads that can vary in condition. Primitive camping spots are available on the grounds, though conditions are harsh and water is limited.

The pines' deep sandy soil sits atop a hard calcium carbonate caliche layer a few inches thick that blocks drainage, holding groundwater near the surface. Seeds from Lost Forest trees germinate faster than other ponderosa seeds, a local adaptation to the arid environment.