Among all of the debates affecting America's national parks, the most enduring—and most intense—is where to draw the line between preservation and use. This is an account of that classic confrontation, as told from the perspective of natural resources and environment. The focus is Yosemite, where debating environmental change is now a century and a quarter old. Yosemite, as the oldest park of its kind, has the longest history of modification. Tourists were familiar with Yosemite Valley well over a decade before the Grand Canyon and Yellowstone were even explored. The issues of park development were raised and debated first in Yosemite. Even today, no other national park more dramatically reflects America's alleged failures to reconcile nature protection with the wants and demands of the visiting public.

The subject, to be sure, is by no means new or unfamiliar. The record is nonetheless incomplete, especially concerning natural scientists, their opinions, and their attempts to influence resource management. The National Park Service Organic Act of 1916 itself left every methodology for management deliberately vague, calling simply for protection of scenery and wild life "in such manner and by such means as will leave them unimpaired for the enjoyment of future generations." But just what was meant by "unimpaired"? In effect, a definition that imprecise extended protection to park resources only by implication. It remained for each generation of Americans to bring its own perspective to the issue, invariably, if only subtly, imposing another viewpoint on existing philosophies of park management and use. Concessionaires in particular, seeking greater profits from increased visitation, consistently advocated visitor comfort and convenience over resource preservation.

That contradiction, among others, forms one basis of this study. I have also examined divergent points of view about what Yosemite ought to be and what it in fact became as each generation of Americans reevaluated the park's purpose and future. The ideal of sanctuary—that Yosemite National Park should represent a vignette of primitive America—has rarely been put to greater test than in Yosemite Valley itself. It is here that the goals of preservation contrast sharply with the expectations of a mobile, affluent society. Nor have preservationists, despite their overriding commitment to the ideal of park sanctuary, been entirely free of responsibility for the effects of human change. Merely by their presence, it stands to reason, preservationists themselves have contributed to a modified environment.

Regardless, studies of environmental change have largely been ignored. In the existing literature about Yosemite, most writers have traced the human history of the park, noting, for example, its colorful explorers, aboriginal inhabitants, innkeepers, and early publicists. In this volume, the social history of the national park is subordinate to the emerging debate regarding the proper management of the natural resource. What follows is an environmental history. People, buildings, and traditions are treated only as they pertain to evolving philosophies of park management and use. To reemphasize, I have focused on two issues: the ideal that Yosemite National Park ought to be managed and enjoyed as a natural sanctuary, and that ideal's simultaneous erosion, caused by increased development pressures generally divorced from biological considerations.

I have therefore tried, wherever possible, to avoid familiar ground. I do not, for example, retrace the footsteps of John Muir. Nor is this a chronology of every person or event in the history of Yosemite National Park. If the reader's favorite individual, anecdote, or story is missing, I stress again that this is a study of the natural environment. Similarly, I have avoided giving another long account of the Hetch Hetchy reservoir, except to underscore its significance as a policy and resource issue. Like biographies of John Muir, detailed histories of the Hetch Hetchy controversy are numerous and easily obtained. There would be little point in my repeating an already familiar theme.

My choice of resource subjects has likewise been selective, determined in part by the importance and availability of original source materials. For example, there is much to be found on bears but considerably less for all other wildlife. My own emphasis is on bears not only because more sources are available but also because no other animal has sparked such sustained and revealing debate. Fire ecology, another important issue, receives greater attention for the earlier history of the park. Modern approaches to natural fire are extensively documented elsewhere; then too the future of fire ecology is once more in doubt, especially in the wake of extensive fires bordering Yosemite in 1987 and the outspoken reaction against fire management policies implemented in the Yellowstone fires of 1988. The issue requires more time for definitive conclusions. One thing is certain: Natural fires will be even more closely monitored than they have been in the past and, it would appear, more often contained or suppressed.

Natural resources, like people and events, appear in the narrative as barometers of change. More than an inventory of every resource, this book examines those resources and environmental issues that provoked redirections in management. Meanwhile, the observance of the centennial of Yosemite National Park, established on October 1, 1890, lends special significance to every resource controversy and its intended or thwarted outcome. So too, June 30, 1989, marked the 125th anniversary of the Yosemite Park Act of 1864, which set aside sixty square miles of territory surrounding Yosemite Valley and the Mariposa Grove of giant sequoias. Although the legislation of 1890 established a national park roughly twenty-five times as large, the park act of 1864 was the first instance of scenic preservation in the United States and thus represented the conceptualization of the national park idea.

In that regard, as well as others discussed here, Yosemite's history is both symbolic and distinctive. Proclaimed a public trust as early as 1864, Yosemite bears the longest evidence of the tension, found in every major park, between preservation and use. As the twentieth century now draws to a close, there is renewed concern about the future of the national parks; any reassessment logically must begin with their philosophy and history. A study of Yosemite's natural environment and resources, as viewed against the backdrop of the park's longest and oldest debate, should help guide modern Americans as they grapple to realize the preservation ideals of their own generation. Among them, perhaps the most significant is the determination that living wonders of the national parks, and not only dramatic scenery, must survive intact through the twenty-first century and beyond.

Vernal Falls.