WASHINGTON (AP) _ The Forest Service is canceling additional logging planned at a national forest in Oregon where dozens of demonstrators were arrested in protests over flood damage and threats to troubled salmon.

Instead, the Forest Service will spend $411,000 to buy back the 1.8 million board feet of standing timber that had been sold to the Rough and Ready Lumber Co. of Cave Junction, Ore., agency officials said Wednesday.

Those old-growth groves represent only about 14 percent of an overall clear-cut logging project, known as the China Left timber sale, at the Siskiyou National Forest in southwest Oregon.

About 12.7 million board feet in the other clear-cut units already has been logged. A board foot is 1 foot square and 1 inch thick. It takes about 10,000 to build a typical single family home.

Over the past 18 months, environmental activists had built blockades, scaled trees and chained themselves to gates to protest the planned logging of the trees, some as old as 500 years.

Michael Lunn, the forest supervisor based in Grants Pass, Ore., said in a cancellation notice sent to Forest Service Chief Mike Dombeck last week that the Sucker Creek in the timber sale area houses one of the largest populations of coho salmon protected under the Endangered Species Act.

He said logging the steep slopes along the creek could accelerate erosion, sending soil into the waters that must be clean and cold for optimum spawning.

``I am unwilling to accept the risk of additional resource damage or environmental degradation associated with the cutting of the remaining unites on China Left timber sale,'' Lunn said.

Earlier plans to go ahead with the logging were based on assumptions that proved to be inaccurate following a strong storm in January that produced a magnitude of floods normally seen only every 50 to 75 years, he said.