Survival of Phellinusweirii in Douglas-fir stumps after logging

Abstract

Stumps and roots of trees harvested 20, 30, and 50 years ago were examined for survival of Phellinusweirii. Survival was compared among sites regenerated to Pseudotsugamenziesii (Douglas-fir) and Alnusrubra (red alder). Distinctive patterns of decay and the persistence of setal hyphae and zone lines after death of the fungus enabled documentation of survival time and of the retreat of P. weirii from roots. Phellinusweirii often died from a decay column without colonizing adjacent sound wood.Data from 1076 roots on 340 stumps were analyzed. After 50 years, the fungus survived in 26% of the stumps and in 11% of the roots sampled. Surface mycelium was present on 17% of the roots after 20 years, 15% after 30 years, and 1% after 50 years. The decrease in survival time was similar on sites presently occupied by red alder or by Douglas-fir. Survival was not correlated with stump diameter or degree of deterioration after 20 and 30 years. In the current stand, trees killed by P. weirii were found within 5 m of 45% of infected stumps after 50 years.