The U.S. Forest Service failed to take into account potential harm to natural resources and damage to an ancient Indian trail when it approved a major forest land swap with Weyerhaeuser in Washington state, a federal appeals court ruled yesterday. The court said Weyerhaeuser, which has already logged part of the land since acquiring it in March 1998, must halt further logging until the USFS reviews the effects of logging on the environment and historical resources. The trade gave the company 4,300 acres from a national forest in exchange for 30,000 acres that had already been logged. Enviros are split on the trade, some asserting that it was a good deal.