Investigations were conducted from 1998- 2000 at the Potlatch Corporation's Cherrylane Seed Orchard near Lewiston, Idaho to evaluate presence and extent of potentially pathogenic fungi on roots of diseased stock and within the soil in current and proposed plantation sites. The most common group of pathogens encountered was Fusarium spp.; F. oxysporum was by far the most common colonizer of tree roots and soil. Phytophthora spp. (P. cacta rum and P. pseudotsugae) and Pythium spp. (P. irregulare and P. ultimum) were also common root and soil colonizers. Cylindrocarpon spp. (C. destructans and C. tenue) were isolated at lower frequencies. Soil solarization with a thin plastic tarp during the summer effectively reduced populations of potential soil-borne pathogens. Managers should continue to monitor pathogen populations on stock and within soil of proposed plantation sites in order to reduce future disease impacts.