The importance of basidiospores of Phellinus (Poria) weirii in spread of laminated root rot in western North America is unknown. In this study, basidiospores of P. weirii were able to germinate and initiate colonization of previously frozen and scalded wood disks cut from nine species of conifer and two species of hardwoods. Colonization was best at temperatures of 15°-20°C when an aqueous suspension of spores in concentrations of 400/ml or greater were sprayed on disks. Disks first sprayed with a soil suspension or buried after inoculation were not colonized by P. weirii. Western redcedar, Sitka spruce, bigleaf maple, and red alder were colonized to a lesser extent than were other species. Sapwood of Douglas-fir was more easily colonized than heartwood. In western forests, temperature conditions similar to those under which colonization was successful probably exist most years during late summer and early autumn. Forest Sci. 22:407-411.