EVERYBODY IN SAN Francisco cares about the parks, but different people care about the parks in different ways. Some people, "active users," see them primarily in terms of recreation. Others, "passive users" and nonusers, view them primarily as open space. Not only do active users and passive users have different uses and expectations for the parks, they also usually are different people.

Passive users and nonusers tend to be homeowners, adults, prosperous, and white. They have yards of their own for barbecues and trips to Tahoe for recreation. Active users tend to be renters, nonwhites, and kids. They need the parks for much, if not all, of their outdoor activities. Passive users tend to be organized into civic groups, and if they or their kids do use the parks for recreation, they play in organized and scheduled groups, teams, and leagues. Active users are not organized into groups and take their play without uniforms or schedules.

There has been conflict between these views of park use from the very beginning. Frederick Law Olmstead, creator and superintendent of New York's Central Park, originally imagined that park as a "pristine nature reserve" and yielded only to concerted political pressure to open the United States' first urban park to the urban public. Nevertheless, the San Francisco park system has managed for more than a century to satisfy both active and passive users with little overt antagonism.

Now, gentrification – the increase in the number, influence, and sense of entitlement of prosperous white homeowners at everyone else's expense – has come to the park system. Supported by a gentrified Recreation and Park Department management, passive users and nonusers have become aggressive advocates of replacing people with plants throughout San Francisco parks. Rec and Park has locked down 15 to 20 percent of the city's playing fields, so no one can use them without a fee and an appointment. It has tried to displace the Haight Ashbury Recycling Center from Kezar Stadium. It has established a so-called Natural Areas Plan (Olmstead's "pristine nature reserve" revisited), which would ban public access to hundreds of acres of park land. And it has worked at establishing a new dog policy to eliminate San Francisco's largest single form of recreation from neighborhood parks.

Because the dog-owning population is the largest, best organized, and most vocal segment of active users, dog owners often serve as the representatives of that group as a whole. As a consequence, conflicts over Rec and Park policies sometimes seem to be conflicts over dogs – or, rather, over dog owners.

True, Rec and Park's most spectacular struggle has been over its dog policy – more people showed up to oppose the Rec and Park Commission on this issue than have ever showed up to attend any San Francisco commission meeting, and more people wrote to oppose the policy than have written on any other San Francisco issue. (To no avail: Rec and Park does not believe in democracy.) Nevertheless, the opposition to the department's latest plans is far more universal than just dog issues.

For example, the fight against the Natural Areas Program was started by the Tree Council. That group objected when Rec and Park clear-cut eucalyptus trees, so that they could be replaced with natural poison oak and sand dunes. The Tree Council was quickly joined by academic ecologists from Stanford University, San Francisco State University, and UC Davis, who thought the department's plans didn't make any sense. The fight for the Recycling Center has been led by representatives from the Haight-Ashbury neighborhood and the recycling community.

For more than a decade, we have fought over gentrification and its effects on jobs, housing, transportation, and other city services. Now we are fighting over gentrification and its effects on the park system. The issue is the same. Shall the parks be run for the benefit of the people who use them, need them, and contribute to them, or shall they be run for the benefit of some spectators somewhere else? This is one I think we can win.