Boeing's plan to expand onto some 500 acres at Charleston International Airport came with a little-noticed but huge environmental victory that may signal the end of a decade-long threat to the future of the Francis Marion National Forest.

For years developers have considered plans to build thousands of new homes on several key plots of privately owned land on the southern and western edge of the forest between Awendaw and Huger. Boeing is preparing to purchase and protect some of that land.

One of the plots, the Keystone tract, borders S.C. Highway 41 near Huger and has been sought by environmentalists since International Paper put it up for sale about a decade ago. The two others, Fairlawn and Nebo, are considered critical to preventing development from endangering the Francis Marion's efforts to re-establish native longleaf pine ecosystems.

The longleaf pine once covered much of the South, but longleaf forests require periodic burning of undergrowth to remain healthy and allow some plants to germinate. The tall pines are generally spared because of their fire resistant bark and because periodic fires reduce the amount and height of undergrowth, causing flames to remain relatively close to the ground.

Historically, fires sparked by lightning scorched vast amounts of forestland and could last for weeks. Now, fires in the Francis Marion are purposefully set and controlled by the U.S. Forest Service. However, such controlled burns are nearly impossible to conduct near populated areas.

Now, Boeing is arranging to buy significant portions of each of those tracts, a total of 3,618 acres, The airplane maker set up the reportedly $12 million deal by using the Lowcountry Open Land Trust and the Open Space Institute to negotiate for the land. The Nature Conservancy also played a role.

The land will be turned over for preservation to the U.S. Forest Service, the S.C. Department of Natural Resources or some similar conservation organization.

Boeing plans to do this as part of its effort to meet regulatory requirements that it mitigate or compensate for the need to fill 154 acres of wetlands on its expansion property near the airport.

'Focus of concern'

Dana Beach, executive director of the Coastal Conservation League, said Boeing didn't need to do anything as big as this in area and significance to meet the wetlands mitigation requirements.

These are among "the most strategically important unprotected parcels in the region," Beach said. "They've been the focus of concern for years. ... Their protection is essential to the future of the area."

Beach said the Keystone tract is appropriately named because development there, near the heart of the forest, would do substantial damage to the Forest Service's ability to maintain the ecosystem.

The parcels are biological and environmental jewels in a national forest that is among the nation's most unique, home to more than 400 species of mammals, birds, amphibians and reptiles and 1,600 species of plants, including 12 types of orchids and 12 species of carnivorous plants.

Beach said that several months ago Boeing sought out various environmental nonprofits, including the conservation league, and federal, state and local environmental agencies to find wetlands mitigation areas that could offer a major impact. The groups basically agreed on these tracts, Beach said.

Longtime conservationist Charles Lane described the Boeing mitigation plan as a huge deal.

Twenty-five years ago, Lane helped create the ACE Basin environmentally protected area southeast of Charleston, one of the largest undeveloped estuaries along the nation's Atlantic Coast. Boeing called on Lane to work with its team and other local organizations to arrange the mitigation deal. This "is a major step forward to protect" the Francis Marion National Forest, Lane said.

Charleston Mayor Joe Riley praised Boeing for making a permanent addition to the Lowcountry environment and the quality of life that make the area so attractive for both residents and visitors.

Joanna Pickup, with Boeing's environmental communications office, said the company "is committed to environmental stewardship and efforts like this support our commitment."

What's so important?

Environmentalists give the following reasons for the significance of each property in the Boeing mitigation plan:

The Keystone tract is seen as an opportunity to connect the Francis Marion to the Cooper River and preserve safe animal passage between the watersheds of the Santee and lower Cooper rivers.

The Fairlawn property is part of a parcel that is No. 1 on the U.S. Forest Service's acquisition list east of the Mississippi, and the deal includes an option to buy more of the tract.

The Nebo tract is expected to become a full public-access park.

The tracts also help unify the huge national forest and connect it to other environmentally protected land.

The Francis Marion is not the unbroken blanket of federally owned land that it appears on most maps. Instead, the border outlines the area in which the Forest Service is authorized to obtain land for the Francis Marion.

Inside that border, the Forest Service owns some 260,000 acres. Another roughly 130,000 acres are privately held in so-called "in-holdings" that pockmark the national forest.

Reach Doug Pardue at 982-3337