SAN FRANCISCO — In what it termed a “cautionary tale” about judges posting on social media about pending cases, the U.S. Court of Appeals for the Ninth Circuit on Thursday turned back a bid by Sierra Pacific Industries Inc. to unwind a $122 million deal the timber giant reached to settle federal claims that it was liable for the 2007 Moonlight Fire, a blaze that consumed nearly 65,000 acres in the Plumas National Forest.

In a 34-page opinion written by Chief Judge Sidney Thomas, the appellate court held Sierra Pacific's allegations that government lawyers withheld pertinent information and induced witnesses to provide misleading testimony didn't make out a claim rising to the level of fraud on the court. The appellate court also turned back Sierra Pacific's argument that Twitter posts by the trial judge overseeing the case showed bias and warranted a recusal.

“Nonetheless,” wrote Thomas, “this case is a cautionary tale about the possible pitfalls of judges engaging in social media activity relating to pending cases, and we reiterate the importance of maintaining the appearance of propriety both on and off the bench.”