The trees of Belt Woods are silent sentinels to the passage of time, wooden Goliaths, with trunks four feet wide at their base that soar 140 feet into the sky. And they are home to 60 species of forest interior songbirds, a concentration unique in North America.

Here, a few miles beyond the Capital Beltway in central Prince George's County, these woods are an island of rural respite in a sea of suburban growth.

But maybe not forever. For years, the forest owners have been trying to develop the area. The number of planned homes has been scaled down, but one small subdivision would be too much for opponents.

It would be a classic conflict between growth and the environment except for one thing. The forest owner is no rapacious developer. It's a trust whose beneficiaries are the Episcopal Diocese of Washington and a local church, St. Barnabas. During the last five years, $764,000 in trust income that might otherwise have been used for religious or charitable purposes has gone to zoning lawyers, engineers and consultants in an effort to replace many of the trees with houses, which produce more yield in dollars.

The unseemly appearance of religious institutions applying the laws of economics to the works of creation has turned Belt Woods into a national cause celebre among environmentalists and self-styled "ecotheologists," inspiring concerts, prayers, protests, pickets and even a '60s-style sit-in. The controversy has been covered in the New York Times, aired on National Public Radio and documented on Maryland Public Television.

"For me, that forest is as important a national treasure as anything in any of the museums in Washington," said Paul Winter, a soprano saxophonist who gave a sunrise Earth Day concert at Belt Woods in April and is producing a compact disc incorporating the recorded sounds of its wood thrushes.

Off and on for almost a year, the owners have been talking to the Trust for Public Land, a national group that has helped save from development about 800,000 acres -- including the area around Henry David Thoreau's famed Walden Pond. The land trust would help raise funds to buy and preserve Belt Woods.

There is hope of a deal, but the parties are still far apart. Negotiations have been glacial and could take months to complete. Or they could fall apart, leaving the woods vulnerable to development.

"Our approach is we want to make this work," said John McDonough, the Belt Woods owners' attorney. "But it's got to work on reasonable terms. We have basic bedrock principles, a fiduciary responsibility to get proper valuation for the property. We're patient. We'll negotiate until we decide we can't reach agreement. But we're optimistic . . . "

As much as $1 million in state funds would be part of a deal, and legislation has been introduced in the General Assembly. But the session ends in April, and the bill still is pending. Said McDonough, "I don't think delay helps anybody." Preserved for a Time

Delay at least for now preserves the beloved woods of W. Seton Belt, whose 17th century ancestors settled in Prince George's County. Belt, who owned 3,200 acres on six farms, had two passions: St. Barnabas, of which he was treasurer, and his trees. When he made out his will in 1944, he stipulated that the trees on his home farm should never be cut down and his 624-acre home farm never sold.

Instead, he wrote, it should become a place where retired clergy could live in his farmhouse, surrounded by his gardens, fields and forest of tulip poplars and white oak trees.

His other farms could be sold, with the proceeds to be placed in a trust administered by Mercantile-Safe Deposit & Trust Co. of Baltimore, along with other assets. Income from the trust would go to St. Barnabas. After Belt died in 1959, at the age of 89, the trust sold some of the other farms. But plans for his farmhouse went up in smoke when fire struck in the 1960s.

The church and diocese tried to build a small residential subdivision on the home farm but were denied zoning. Then in 1976, the trustees obtained a court reinterpretation of Belt's will that permitted them to sell and log the farm.

In 1981, a New Jersey firm chopped down 563 oak and tulip trees for veneer. Three years later, the trust sold the state 109 acres containing the oldest trees as a nature preserve for $628,000. That left 515 acres undeveloped.

Although the original beneficiary was St. Barnabas, the court said the Washington Diocese would henceforth receive half. St. Barnabas would use its trust income to maintain its Queen Anne School, a private preparatory academy adjacent to the church. Diocese money would be earmarked to help retired clergy.

Renewing development efforts, the trust hired politically connected zoning lawyers and engineers and filed for the necessary approvals. Those efforts sparked a broad backlash. An ad hoc Coalition to Save Belt Woods was formed, then an Episcopal Seton Belt Committee. Another group, the Western Shore Conservancy, came into being to acquire and preserve the property. A county task force was formed to forge a compromise; it failed.

The church argued that it already had "saved" Belt Woods when it sold the "virgin tract" to the state and that its development would preserve enough trees. But environmentalists argued that more woods must be saved to maintain a "biodiversity preserve" for the cherished songbirds.

In both national and diocesan forums, the church adopted pro-environment positions, even as it pressed ahead on Belt Woods development. Said Pam Cooper, a legal secretary and Belt Woods neighbor who founded the Western Shore Conservancy: "You can't have it both ways. You can't support development and then adopt resolutions saying you're going to protect the environment. You either do or you don't."

County approval of the project was blocked by a court challenge in April of 13.7 acres designated for "conservation" rather than "preservation." Opponents successfully argued the former meant that there could be logging as long as new trees were planted. There were further threats of legal action over plans to lay sewer lines through wetlands.

The Rev. Canon Patricia M. Thomas, the diocesan administrator, complained that the court challenges -- not the church's position -- were resulting in high legal expenses. Publicly and privately, the parties alternately expressed both frustration and goodwill.

With the asking price set at $9.7 million, the Western Shore Conservancy made an initial offer; the diocese demurred. The conservancy brought in the national land trust to broker the deal, and a formal offer was tendered in July. A counteroffer came in late November and was found wanting, but the dialogue continues.

Both sides say they remain cautiously optimistic. Meanwhile, the preservationists intend to keep the issue in public view. At the diocese convention Jan. 27, they passed out brochures and offered a resolution that urged sale of Belt Woods to the Trust for Public Lands.

Homosexuality in the church dominated the conclave at the National Cathedral, and the Belt Woods issue was among several that never made it to the floor. But, Thomas said, "I didn't see any problem with passage of the resolution. We're getting closer, and I think we're going to come up with something acceptable within six months."

With enormous legal and environmental hurdles facing any developer of the property, the Belt Trust hasn't exactly been flooded with offers. There is no other party with whom it is negotiating, McDonough said. A Lifestyle's Last Vestiges

Across Church Road from the woods, the Grovehurst and Twelve Oaks subdivisions take their names from their venerable neighbor. Inside the forest, the human population is four. They are the Walkers, a family that worked for Belt, and, as much as the songbirds, they are an endangered species.

They grow tobacco and soybeans in the fields and hunt for rabbits in the forest. Whether the woods are preserved or developed, the Walkers' days there are numbered.

"My grandmother was born here," said Rose Ellen Walker, 55, about Rose Wood, who ironed for Belt, lived rent free and died in 1962. "You hear so much, it keeps you in an uproar, I guess. I've been here all my life. Don't know where I'm gonna go."

Pam Cooper listened sympathetically but could give no assurances. Then Cooper left the Walkers to ponder their uncertain future and headed for Belt's grave.

From time to time, Cooper places fresh flowers at the grave behind old St. Barnabas church, erected in 1704. The other day, she didn't, but a wreath and red ribbon rested anonymously on the ground by his headstone.

"Well," she mused, "he still has a friend." CAPTION: Pam Cooper, a Belt Woods neighbor who founded the Western Shore Conservancy, looks up at giant trees in Belt Woods in Prince George's County. CAPTION: Outside her house, Rose Ellen Walker, 55, talks about living in Belt Woods, where her family farms. "My grandmother was born here," she says.