The Washington Park Arboretum in Seattle is the scene of a crime. Staffers noticed Wednesday that the Keteleeria evelyniana, one of the arboretum's rarest trees, was missing. Only a stump remained at the spot where the 7-foot tall tree once stood. Randall Hitchin, the plant collections manager for the University of Washington Botanical Gardens, says the tree is a threatened species that resembles a conifer.