Gettysburg, Pa. ? Apple trees have been planted, wood fences restored and power lines buried in recent years to transform the Civil War battlefield in Gettysburg to the way it looked when Union and Confederate forces clashed on farmers’ fields in 1863.

But preservationists now worry that the national military park in Pennsylvania’s picturesque fruit belt soon may be in the shadow of high-powered transmission lines.

It is not just Gettysburg that worries them as a result of a 2005 law that gave federal regulators new authority over where power lines are built. They fear the law could place hundreds of national and state parks and other protected sites in the Northeast and Southwest in or near the path of massive power lines.

“They’re not little modest poles that you wouldn’t notice,” said Joy Oakes, senior regional director at the National Parks Conservation Association.

The law was enacted in response to power companies’ complaints that local and state authorities, which historically have decided where power lines go, were reluctant to approve them – often because of residents’ opposition. The stalemate, according to the companies, contributed to blackouts such as the one in 2003 that swept from Ohio to New York City.

Using the law, the Energy Department this year proposed making two large swaths of land in the Northeast and Southwest “national interest” corridors. If the corridors are approved by Energy Secretary Samuel Bodman, federal regulators can order power lines built in them, regardless of state and local opposition.

The Wilderness Society estimates that millions of acres of wildlife refuges, cemeteries, national seashores, protected wilderness, national parks and other types of protected land are within the proposed corridors.

Environmental advocates contend the corridors were drawn broadly to make it difficult to tell where the power lines would go. They say the department should have done a thorough environmental analysis and declared protected areas off-limits before proposing them.

The department is proposing an “overbroad solution” that “bypasses important legal and procedural safeguards,” said Nada Culver, the Wilderness Society’s senior counsel.

The Energy Department says it would require a full environmental and cultural review before federal regulators could order a line built and alternatives would have to be considered.

The Energy Department, which estimates electricity demand will grow 39 percent from 2005 to 2030 in the residential sector and 63 percent in the commercial sector, may propose other high-priority corridors elsewhere. An estimated $31.5 billion will be spent to improve the nation’s transmission system from 2006 to 2009, according to the Edison Electric Institute.

The proposed East Coast corridor would run north from Virginia, and include most of Maryland, all of New Jersey and Delaware and large sections of New York, Ohio, Pennsylvania and West Virginia. The Southwest one would stretch from Southern California into Arizona and Nevada.