Sandstrom was born March 20, 1939, in Longview, Washington, to Harold and Ethel (McManus) Sandstrom. He attended the University of Oregon and Oregon State University, graduating with a bachelor's in Forest Management in 1967.

He interrupted his education between 1963 and 1965 for military service in Vietnam and Germany. He worked for several timber companies after graduation as a forester and forest engineer. In the late 1980s he left his position with MacMillan Bloedel in British Columbia and moved to Corvallis.

He worked on several research projects with OSU and the Forest Service, including the study of early forest land surveys and timber cruise records. Scientists are using his work to study the history of European-American land use in the region, to determine the ages and structures of the region's forests in historical times, and to build models of carbon use and cycling by forests.

He was keenly interested in the history of logging and railroads in the Northwest. "Harold became an invaluable source of information on logging history in western Oregon, especially in the Coast Range, and he was working on maps providing locations of former logging railroads," says Kermit Cromack, professor in the Forest Science department and a long-time colleague and friend. "Though that era has long passed into history, the impacts of that management era and of other events, such as the Tillamook Burn, are of continuing interest in current issues confronting forest management."

Sandstrom is survived by his daughter, Jocelyn, of Victoria, B.C., and a long-time friend, Doris Tilles of Corvallis.