Vitality of Norway spruce fine roots in stands infected by Heterobasidion annosum

Abstract

Normally, infection by Heterobasidion annosum does not affect the fine roots of Norway spruce. Thus, mycorrhizas may be found with rot-affected conifers. The objective of the given study was to compare the morphological indices and mycorrhization of fine roots for rot-infected and healthy Norway spruce trees. The root samples were collected on 14 plots. In 6 of the plots H. annsoum was established. The plots were either on mineral soils or peaty soils. The major morphological indices of fine roots (such as root length, volume, number of root tips) were found to be substantially higher (�����=0,05) for the plots with only healthy Norway spruce trees. Twisted, irregularly thickened mycorrhizas of bunch-like distribution were dominant for the plots with H. annosum infected Norway spruce trees.