The preservation movement contrasted sharply with the conservation movement of the progressive era.

The conservation movement looked to the planned use of natural resources, whereas the preservation movement looked to stopping the despoliation of natural areas.  The leading preservationist of these years was John Muir (1838-1914).

John Muir
(Image from Corbis Beckman)
Because of this difference, the preservation movement and the conservation movement were sometimes in conflict with one another.  The most publicized controversy of the early twentieth century was the plan of the city of San Francisco to build a dam flooding the beautiful Hetch-Hetchy valley in California's Sierra Nevada mountains in order to supply the growing city with an adequate supply of fresh water. (Learn more about the Hetch-Hetchy valley!)

The differences between conservation and preservation were perhaps less acute in the early years of the twentieth century than they were eventually to become after the population of the United States expanded dramatically.  In the absence of population pressures, at least in the western part of the nation, the two movements could co-exist peacefully except for incidents like the construction of the   dam.

Theodore Roosevelt supported both conservation and preservation. Roosevelt moved vigorously to expand the nation's infant system of national parks and national monuments in order to prevent commercial and private exploitation of important pristine natural areas.