A large swath of land cleared of most of its trees at the home of Robert J. Stevens, former CEO of Lockheed Martin, on Oct. 4 in Potomac. The National Park Service is not satisfied with a Montgomery County plan for Stevens to reforest the area, which overlooks the Potomac River and the C&O Canal. (Jahi Chikwendiu/The Washington Post)

After the former chief executive of Lockheed Martin clear-cut more than an acre of protected land near his Potomac mansion last year, environmentalists were outraged, comparing it to when Daniel Snyder, the owner of the Washington Redskins, cut down 130 trees on his nearby estate.

Montgomery County officials fined Robert J. Stevens $1,000 and pledged to come up with a plan that would force him to reforest the area, which overlooks the Potomac River and the C&O Canal.

But now the National Park Service, which, like the county, prohibits tree removal near the canal, says the county’s plan not only fails to fix the damage but allows Stevens a better view than he had before.

After months of discussion with Montgomery officials, Stevens agreed in December to plant 400 trees, grasses, shrubs and wildflowers on 1.3 acres surrounding his home.

But Kevin Brandt, superintendent of the C&O Canal National Historical Park, said Stevens will need to do much more planting to restore an area once thick with oak and beech trees, some more than 80 feet tall and more than 100 years old.

Experts say it could take as long as 50 years to restore the tract.

“Mr. Stevens had not only violated the NPS scenic easement but may also be liable for damages to the NPS,” Brandt wrote in a Jan. 15 letter to the Montgomery Planning Department.

The Montgomery plan also allows Stevens to plant a wildflower garden near his house, which Planning Department environmental chief Mark Pfefferle said would help stabilize the property and prevent erosion. Letters from Brandt made no mention of the garden but noted that the plan “appear[s] to envision a human-managed landscape and will not result in the regeneration of a naturalized forest.”

Park Police spokesman Paul Brooks said federal officials are continuing an investigation of the tree-cutting. No charges have been brought, he said. The matter is under review at the Department of Justice.

Federal regulations do not allow a landowner in designated areas near the park to clear trees and debris except when there is a hazard. Violating that prohibition can result in federal fines of up to $1,000 per incident — which could be calculated on a per-tree basis — and a possible one-year prison term, according to federal tree-protection laws. Montgomery prohibits any cutting without specific permission.

Stevens, 61, was head of Lockheed Martin, the defense contractor based in Bethesda, for more than eight years.

He paid the county’s $1,000 fine and has said through his attorney that he regretted not getting approval and would work to restore the land.

Former U.S. attorney Chuck Rosenberg, Stevens’s attorney, said in an e-mail Thursday that Stevens cleared the area to remove hazards after the June 29 high-wind “derecho” storm.

“When a devastating summer storm severely damaged many of those trees and created a significant safety hazard, [Stevens] hired certified professionals to remove only the damaged trees while mak[ing] the property safe and while protecting undamaged trees — permissible actions under the federal scenic easement,” Rosenberg’s e-mail said.

He said the clear-cutting did not improve Stevens’s view.

Stevens stepped down in December as the second-highest-paid aerospace executive in the nation, according to Forbes magazine. His compensation package in 2011 was $25.3 million. His Merry-Go-Round Farm mansion, located about two miles upstream from Snyder’s estate, was assessed at $2.78 million late last year.

Property owners in protected areas near the canal are made aware of their obligations to preserve natural vistas for people on the canal and towpath when they purchase property as well as in an annual letter from the Park Service. Montgomery County maintains an online database of its protected areas.

Tree-cutting is a sensitive issue at the Park Service, where officials were criticized in a 2006 Interior Department inspector general’s report for their role in allowing tree-cutting at Snyder’s Potomac home. Brandt was park superintendent at the time. The report found that another Park Service employee had helped broker a deal to allow Snyder’s tree-cutting on 1.3 acres, which substantially improved his view of the canal and the Potomac.

Snyder denied cutting trees to improve his view.

Brandt’s letters also cited other deficiencies in the Montgomery plan.

He said it inaccurately depicts trees on the barren landscape that are no longer there. Stevens should be required to plant more large trees in those spots, plant faster-growing species, and pay an approved contractor to monitor the site for 15 years, not the two years the county stipulated, Brandt said.

Chris Stubbs, chief of resources management for the park, said despite their disagreements, the Park Service and the county “are in a partnership situation” and are meeting Friday to try to sort things out.

In the Snyder case, Montgomery’s planning agency, which had not given Snyder a permit, required him to pay $37,000 to a tree bank to purchase and protect three acres in another part of the county. Snyder also agreed to replant the deforested land and put an additional five acres of his property in a protective easement.