William Whyte, author of the "The Last Landscape," said, "The less of our landscape there is to save, the better our chances are of saving it."

I hope he is right because two recent studies on the loss of green space in our region -- the Metropolitan Washington Council of Governments study [Metro, May 22] and a joint report by the Chesapeake Bay Foundation and American Farmland Trust -- indicate that we are running out of time to save what we have left. The studies report that the greater Washington region loses more than 20,000 acres of green space a year and that the rate of land consumption is accelerating. Nationwide, land was converted for development at a rate of 2.2 million acres a year between 1992 and 1997 -- nearly double the pace of development in the previous decade. In our area, the accelerated consumption and fragmentation of open land is profoundly affecting the quality of our air and water and of life itself.

Why are we consuming land at such a rapid rate, and what can we do about it?

The answer to the first question is simple.

As average family size in the region has gone down, the amount of land used by each person has gone up. Large-lot subdivisions are devouring land, and the footprint of conventional commercial development has expanded.

In 1960 we had seven square feet of retail space per person. Today we have 38 square feet of retail space per person. A generation ago, a typical 200,000-square-foot retailer was a multistory department store. Today, the typical big-box retailer is a one-story building covering three or four acres surrounded by 20 or 30 acres of parking.

To change this pattern of residential and commercial development, we must make it easier to build "conservation" developments, which save open space, reduce infrastructure costs and boost property values. For example, Eco-Village in Loudoun County protects more than 70 percent of its land by clustering houses. In Gaithersburg, Target is housed in a two-story building with a four-deck garage, which greatly reduces the amount of land it consumes and helps it fit in better with the surrounding community.

We also need a long-range conservation plan for the region. Green infrastructure should receive the same planning consideration that manmade infrastructure receives. Every jurisdiction in our area has a long-range transportation plan, along with plans to upgrade sewage-treatment plants and other infrastructure. We should have similar plans for preserving natural infrastructure.

This is not just an environmental call to arms. Conservation planning can provide predictability and certainty for local governments, environmentalists and developers. It also can reduce opposition to development by assuring citizens that not every patch of green will be developed.

In addition to preserving wildlife habitat and biodiversity, protecting green infrastructure offers increased recreational opportunities, boosts property values and improves livability; it also can reduce the cost for water treatment and flood control.

To be successful, conservation planning must include local governments, nonprofit groups, landowners and developers. The region as a whole must be involved to protect blocks of green space that cross jurisdictional lines. The Conservation Fund is working with communities across the country to create strategies that result in smart conservation and smart development. On Maryland's Eastern Shore, for example, it is in partnership with Talbot County, which has a fragile system of islands and peninsulas making up almost 600 miles of the Chesapeake Bay's shoreline.

The fund and the county worked together on a plan for development and conservation on 168,000 acres of woodlands, wetlands, farm fields and historic communities. The plan will help Talbot identify and prioritize areas for conservation, while providing a framework for promoting conservation and protecting the county's economic base.

With some foresight now, future generations will look back on our conservation efforts with gratitude.

-- Edward T. McMahon

is vice president for land-use programs at the Conservation Fund.