INDEX — An anonymous donor pledged to pitch in $500,000 to protect a mountain ridge near Index from logging, a grass-roots group of residents and outdoor enthusiasts said Tuesday.

“A shock, total shock,” said Louise Lindgren, president of the Friends of Heybrook Ridge. “We were a long way from our goal.”

The nonprofit group is scrambling to raise $1.3 million to buy about 130 acres of mature forest from a logging company. The money needs to be secured by June 30 or Heybrook Ridge is likely to be logged by the property owner.

Backers for the preservation of Heybrook Ridge hope to create hiking trails in the forest and develop educational programs to let people learn about the ecosystem, said Lindgren, a longtime resident of Index, population 150, just off U.S. 2 in the Skykomish Valley.

“It’s not only about stopping logging,” she said. “It’s also about how to turn the forest into a different use.”

The town was incorporated in 1907 and thrived on logging and mining. Now few people there make a living that way.

In late 2006, W.B. Foresters in Stanwood proposed logging Heybrook Ridge, saying that alders in the area are mature and need to be logged before they die. The company owns the forest and has a state permit to harvest trees there.

People in Index protested, saying that the logging would ruin the area’s scenic view and lower their property values.

The company later withdrew its logging application after state officials determined there is fish habitat in the area.

Index residents formed the nonprofit group to preserve the area. The group has raised about $35,000 through fundraising events, Lindgren said.

Debbie Buse, the logging company’s business manager, said the company is open to selling the 130 acres to the group as long as the money is raised.

“This group has been very impressive,” Buse said. “They’ve been very active.”

The group has teamed up with Cascade Land Conservancy, a nonprofit conservation organization. The $500,000 pledge makes the effort to preserve the ridge realistic, supporters said.

“We are quite confident that we can raise this money,” Lindgren said.

Reporter Yoshiaki Nohara: 425-339-3029 or ynohara@heraldnet.com.