This paper examines how the USDA Forest Service (USFS) adapted to the changing needs of American society in its industrial (about 1900'1969) and post-industrial (1970 up to present) stages of socio economic development. Several marker events in Forest Service adaptation to a post-industrial American society are examined (e.g., Bitterroot clearcutting controversy). These events illustrate American cultural changes that have moved the agency toward its current 'ecosystem management' era of organizational evolution. Shifts and trends in agency values, policies, structures and operation to embrace and implement ecosystem management are examined.