PORTLAND – The state’s largest environmental advocacy organization on Thursday came out in opposition to a massive development being proposed for the Moosehead Lake region by Plum Creek Timber Co.

The Natural Resources Council of Maine said Plum Creek’s plan is out of scale and out of character for the region made famous by Henry David Thoreau and should be rejected by the state’s Land Use Regulation Commission, which is reviewing the project.

Plum Creek submitted a 570-page plan in April calling for 975 house lots, two resorts, three recreational-vehicle parks, a golf course, a marina and rental cabins around Moosehead Lake. The development is the largest subdivision ever proposed in Maine.

Brownie Carson, executive director of NRCM, said the proposal is all about profits for an out-of-state publicly traded company, which last year had revenues of $1.5 billion.

“This plan would chop into the heart of Maine’s North Woods, dwarf area towns and send roads, power lines, commercial development and more than 1,000 buildings sprawling into what is now remote and spectacular forests, lakes and mountains,” he said at a press conference at Portland City Hall.

Jim Lehner, Plum Creek’s regional general manager, defended the plan, saying it leaves 98 percent of the land unchanged, preserves property as working forest and restricts future development. The plan, he said, will stimulate economic development and create much-needed jobs.

Lehner said he recently came across a map of Moosehead Lake that was hand-drawn in 1900 showing hotels lining the shore and steamer routes around the lake.

“It’s a tradition. Camp lot development and resorts are a tradition that have been in the area for 100 years,” he said.

Plum Creek, based in Seattle, owns about 900,000 acres in Maine that it bought seven years ago from Sappi Inc. Nationwide, the company owns about 8 million acres of woodlands.

Last December, Plum Creek announced its intention to develop its holdings around Moosehead Lake. It formally submitted the plan with LURC in April.

The project involves a total of 426,000 acres, of which about 10,000 are slated for development. The development would include 575 shorefront lots and 400 back lots.

Plum Creek says the plan puts in place protective easements on more than 100 miles of snowmobile and hiking trails, up to 180 miles of shorefront property and on 55 ponds. The company expects most of the development to take place over the next 10 to 15 years.

Carson said despite the claims by Plum Creek, the plan is “fundamentally at odds with the rugged country and way of life for which the Moosehead region is known and loved.” The NRCM is not opposed to all development, but it should be measured and in keeping with the region’s character, he said.

As for employment and economic development, the project would provide a spike in vacation home construction jobs for five to seven years but not much else, said Mike Turcotte, who was executive director of the Moosehead Lake Region Chamber of Commerce until earlier this month.

People who own the new homes or come to vacation would end up spending their money at the stores, gas stations and restaurants inside the resorts, not in Greenville, he maintained. The result, he said, would be like big-box stores opening up outside a small town and draining business from downtown businesses.

A number of town officials, state legislators, business owners, outdoorsmen and others in the region have lined up in support of the project. They say Plum Creek’s plan considers the needs of local communities while striking a balance between conservation and development.

Others have come out against the plan, and Carson said he expects opposition to grow in the months ahead as people digest the plan and learn more about the details.

“This is the nation’s largest undeveloped area east of the Mississippi, and when it’s gone it’s gone,” he said. “The real question is: What kind of legacy do we want to leave our children?”