ARMILLARIA ROOT DISEASE, STAND CHARACTERISTICS, AND SOIL PROPERTIES IN YOUNG LODGEPOLE PINE

Thirty six lodgepole pine stands in west-central Alberta, ranging in a ge from 9 to 28 yr of age, were surveyed for Armillaria root disease m ortality. Selected stand characteristics and edaphic factors were reco rded in each stand to determine if there was a relationship between th ese factors and Armillaria root disease. Data was analysed using a mul tivariate linear regression. A statistically significant relationship was found between sand content, ammonium (NH4+) concentration and Armi llaria root disease. The incidence of Armillaria root disease increase d significantly with increasing sand content of the surface mineral ho rizon and decreasing NH4+ concentration of the surface organic horizon (LFH). Stand age, density, elevation, soil pH, depth of the surface o rganic horizon (LFH), calcium (Ca), phosphorus (P), potassium (K), mag nesium (Mg), and sulfur (S) did not have a significant effect on the a mount of mortality. (C) 1998 Elsevier Science B.V.