Federal authorities believe that two fires in the Northwest may have been set early on Monday by environmentalists opposed to genetic engineering. The arson at the University of Washington in Seattle appeared targeted at research to make genetically engineered trees more commercially viable, but authorities said the fire mostly destroyed or damaged work on endangered species, wetlands restoration, and urban forestry and gardening. Managers of an Oregon poplar nursery — where arsonists set fires and left the spray-painted words "You cannot control what is wild" and "ELF" — said they did not grow genetically engineered trees there, though the land used to be owned by a university genetics group. In the past, the Earth Liberation Front has claimed responsibility for arson and vandalism against the Vail ski resort in Colorado, a lumber yard in Oregon, and housing developments on Long Island.