Commissioners in Beaverhead and Madison counties were surprised when U.S. Sen. Max Baucus signed on as a co-sponsor to U.S. Sen. Jon Tester's wilderness bill.

Commissioners from both southwestern Montana counties said they thought they had an agreement with Baucus that he would not voice any support for the bill until local governments were comfortable with it.

In part, the bill would set aside 505,000 acres of land as wilderness and require the U.S. Forest Service to harvest at least 7,000 acres of timber per year for 10 years.

Beaverhead and Madison county elected leaders said they are concerned about how the wilderness designation would affect ranchers and county tax proceeds.

Baucus spokesman Ty Matsdorf said the senator decided to support the bill after carefully studying the legislation.