ECTOMYCORRHIZAE AND GROWTH OF DOUGLAS-FIR SEEDLINGS PREINOCULATED WITH RHIZOPOGON-VINICOLOR AND OUTPLANTED ON EASTERN VANCOUVER-ISLAND

Ectomycorrhizal colonization of container-grown Pseudotsuga menziesii (Mirb.) Franco (Douglas-fir) inoculated with Rhizopogon vinicolor A.H. Smith was determined after cold storage and after one growing season on a clearcut on eastern Vancouver Island. Inoculated Douglas-fir seedlings were taller than noninoculated controls when outplanted but, perhaps because of browse damage, no growth differences were found after one field season. Rhizopogon vinicolor colonized all of the inoculated but none of the control seedlings examined after cold storage. Volunteer Thelephora terrestris Fr. colonized almost half of the control and 10% of the inoculated seedlings before outplanting. After one field season, inoculated and control seedlings were colonized by 15 ectomycorrhizal fungi each, only eight of which were found on both. Rhizopogon vinicolor persisted on the roots of inoculated plants, but was also present in the field soil since the control seedlings also bore these mycorrhizae after one growing season. The relative abundance of T. terrestris decreased from the nursery to the field. The other common ectomycorrhizae in the field included Mycelium radicis atrovirens Melin, Cenococcum geophilum Fr., and types resembling Tuber and Endogone.