PORTLAND (AP) – About 312,000 acres of working forest in eastern Maine will be permanently protected from further development under one of the nation’s largest conservation easements, officials announced Tuesday.

The Conservation Fund and the New England Forestry Foundation plan to use the nearly $7 million grant to restrict development and ensure sustainable forestry practices on land that reaches into Washington and Penobscot counties.

“This is one of the last intact, vast forest landscapes Down East,” said Larry Selzer, president of The Conservation Fund. “You would be hard pressed to find anyone in the state of Maine who would have anything negative to say about this.”

The easement, which becomes effective immediately, will be funded with money from Acres for America, a partnership program between the National Fish and Wildlife Foundation and Wal-Mart. The corporation has pledged $35 million over the next decade to help protect natural resources and the environment.

Connecting more than 1 million acres of wilderness, including 600,000 acres in New Brunswick and 200,000 acres of state, federal and Indian lands in Maine, the easement will also conserve about 360 miles of lake shoreline and safeguard habitat for more than 185 species of birds.

“It’s a great gift, it’s a great surprise, and it’s a very good deal. You buy up development rights and you buy up access,” said Pat McGowan, commissioner of the state conservation department.

The New England Forest Foundation plans to match the money to raise the nearly $13 million to buy the easement, which will be held by Wagner Forest Management, which currently manages the property.

Other partners in the project include The Nature Conservancy, the State of Maine, National Wildlife Federation and Wildlife Forever and Downeast Lakes Land Trust, which many have credited as the force behind the project.

“This project was incubated locally. It was designed locally, and it has been supported top to bottom by local people who have taken a boot strap effort to solve the problem of a changing landscape,” said Amos Eno, executive director of the New England Forestry Foundation.