Mark Neal Beach, 62, who had managed development programs for several philanthropic and educational organizations in the Washington area and in Michigan, died Monday after falling from a tractor while mowing a field at his home in Waterford, Va.

He retired earlier this year as vice president of the Nature Conservancy. He also had been development director of the National Trust for Historic Preservation, development director for the Washington Cathedral and consultant on foundation gifts for Interfaith Metropolitan Teological Education Inc.

Before coming to this area in 1967, Mr. Beach was development director of Wayne State University in Detroit and executive director of the Greater Detroit Hospital Fund.

He was born in Smith Creek, Mich., and was a graduate of the University of Michigan.

In recent years, while living in Waterford, Mr. Beach had been a private development consultant to World Neighbors Inc. of Oklahoma City and the Center for TV and the Humanities in Atlanta.

He had served on the boards of directors of the Waterford Foundation and the Loudoun County Day School of Leesburg, Va.

He is survived by his wife, Jill, of the home in Waterford; eight children, Carrie Smith Beach, Dana Lee Storm and Charles, also of the home, William B., of Detroit, Barbara Spencer, of Big Rapids, Mich., Patti Forman, of Ann Arbor, Mich., Marcia Lyons, of Great Falls, and Amy Beach, of Ann Arbor; his stepmother, Lillian Beach, of Ferndale, Mich.; two sisters, Helen Lake, of Maple City, Mich., and Eleanor Keeley, of Detroit, and three grandchildren.

The family suggests that expressions of sympathy be in the form of contributions to the Loudoun Memorial Hospital Longterm Care Unit. CAPTION: Picture, MARK NEAL BEACH