The 6,495 hectares (25.08 sq mi) experimental forest was originally established in 1933 and was designated as a biosphere reserve in 1976.

The Fern Canyon Research Natural Area is in the remote eastern part the San Dimas reserve.

[5] Studies at San Dimas have provided valuable information on air pollution, fire effects, erosion, hydrology, and plants and animals in southern California watersheds.

The area also provides opportunities for ecological research to many nearby colleges, universities and governmental agencies.

This article incorporates public domain material from websites or documents of the United States Forest Service.