When Boeing made it possible to preserve 4,000 acres in and near the Francis Marion National Forest north of Mount Pleasant, it did a lot more. It encouraged nearby property owners to place conservation easements on their holdings.

And in an area where development is a constant threat to the lush landscape and its rare birds, animals and trees, conservation easements play a vital role.

That's one very important reason that environmentalists are eager for the 9,000-acre Cainhoy Plantation to be handled with care. Too-dense development or misplaced zoning could compromise an extraordinary piece of property, and it could also discourage nearby property owners from conserving their lands. From their perspective, being part of a healthy greenbelt is much more appealing than conserving land next to dense development.

As long as properties don't provide some measure of conservation protection, they are potential chinks in the greenbelt that all but surrounds the Charleston area and makes the Lowcountry environment noteworthy as well as beautiful.

Elizabeth Hagood, executive director of the Lowcountry Open Land Trust, says that an ill-considered development at Cainhoy Plantation could impair the ongoing conservation initiative.

For example, inappropriate development could prevent burning in the Francis Marion National Forest, which protects natural plant life - especially longleaf pine trees whose numbers have diminished dramatically across the Southeast.

The owners of Cainhoy Plantation, for decades used as by the Guggenheim family for hunting and entertaining, intend to set aside land directly across the highway from the National Forest for light industrial use. That could stop controlled burning, at the expense of the fauna and flora.

Mrs. Hagood has offered the developer the benefit of LOLT's land planning expertise and assistance. She believes that development would be suitable in the southern portion of the property. The portion north of Clements Ferry Road should establish a transition between suburbs and the forest, as well as other natural, undeveloped land.

Matt Sloan, who represents the property owners, points out that the property to be developed is in a busy area that connects the city of Charleston and Mount Pleasant. He believes the master plan being considered for Cainhoy Plantation is respectful of the natural environment, even as it provides for some 20,000 new residents.

Cainhoy Plantation is indeed in the city of Charleston, but it is also in an area valued for its large conservation tracts and undeveloped beauty. Indeed, Mrs. Hagood says it is "one of the most intact historic natural landscapes in the country" and could be to the north of Charleston what the ACE Basin is to its south.

About 9,000 acres of private lands in that East Cooper area have been conserved, she says, but just as many have not. Her goal is to protect it all.

Reaching that goal would benefit Cainhoy Plantation's owners. It is the area's extraordinary natural assets that make Cainhoy an appealing place to live. But achieving and maintaining a greenbelt will be much more difficult if Cainhoy is developed in a way that diminishes those assets. And it would be an environmental tragedy.

Finding the proper balance is a difficult process. Cainhoy Plantation is a business opportunity for its owners. To others its worth is in its natural assets and historic and cultural significance.

At this point, too many objections, questions and inconsistencies remain for the project to move forward.

The Cainhoy master plan will be taken to the city's Planning Commission Wednesday. Members would be wise to defer making a decision until there is more consensus about this mammoth project, located in an area where conservation has been widely embraced.

So far, there appears to be a lack of common ground.