Annosus root rot caused by the fungus Heterobasidion annosum (fr.) Bref., causes a destructive root and butt rot of many important tree species throughout the world. Presently, methods for determining disease incidence and severity and destructive. In this study, the most effective, non-destructive, disease severity prediction parameters were determined for thinned Pinus taeda plantations growing on high hazard sites. Above-ground tree parameters and 0.03m³ soil-root (SR) samples were used as predictions variables. Base-line data for predictions was obtained by excavations of 190 tree root system from plantations located in Eastern Virginia and Central Alabama. Multiple regression analysis indicated that stem diameter (DBH), radical growth (GR5) live crown ration (LCR), and SR samples were the most effective parameters in explaining the variation in the root sustem colonizatio levels of the plot trees studied. / M.S.