MORTALITY CAUSED BY ARMILLARIA ROOT ROT, PERIDERMIUM RUSTS AND OTHER DESTRUCTIVE AGENTS IN LODGEPOLE PINE REGENERATION

Surveys of diseases and other forms of damage in naturally regenerated lodgepole pine were carried out in 1959 and 1962 near Robb, Alberta in an area that had been burned in May, 1941. Eighteen and one-half per cent of the trees on seven 0.05-acre plots were dead in 1959. The additional mortality on the same plots from 1959 to 1962 was 27.7 per cent. The seemingly high mortality was not considered excessive, in light of the large numbers of trees remaining on the plots, but further examinations will show if the present high mortality rate is sustained. The most important destructive agent up to 1962 was Armillaria mellea (Vahl ex Fr.) Quél. The most important non-infectious destructive agents were game and rodents.