Effect of site preparation on Armillaria ostoyae infection and growth of spruce after partial cutting in a Boreal Mixedwood Forest

Abstract

Site preparations methods, mixing, scalping and no treatments (control), were evaluated to promote establishment of white and black spruce and reduce mortality by Armillaria ostoyae in partial cuts of Boreal Mixedwoods of northern Ontario. Soil mixing using a Meri Crusher MJ80 reduced the initial inoculum potential of A. ostoyae. Tree mortality was determined each year in the spring and fall for 15 years and all deaths resulted from infections by A. ostoyae. Diameters and heights were assessed after 1, 3, 5, 10 and 15 growing seasons. Overall mortality was lower with Picea glauca but was not a result of the different site preparation methods. Mortality of Picea mariana was lower in the screefed treatment. Growth of both species was better in the mixed treatment.