An initial look at mycorrhizal fungi and inoculum potential in high elevation forests

Abstract

Mycorrhizae are symbiotic associations that improve plant nutrition in the competitive biological communities that inhabit forest soils. The goal of this research was to determine if cutblock size and distance from the standing timber has any effect on the diversity of ectomycorrhizal fungi available for colonization of outplanted seedlings. During the winter of 1994�95, the Sicamous Creek Silvicultural Systems Study (Engelmann Spruce-Subalpine Fir Wet-Cold Biogeoclimatic Variant) was harvested. Four treatments were sampled in this study: no harvesting, 0.1-ha, 1-ha and 10-ha cutblocks. In the first summer following logging, there was no difference in the numbers or diversity of ectomycorrhizae in soil cores removed from the cutblocks and the forests. The number of ectomycorrhizae in the cutblocks decreased substantially by the second summer, and very few were present by the third summer. Moreover, the diversity of mycorrhizae was significantly reduced at a distance of 16 m or more from the forest edge. After 13 weeks of growth in the field, the number of types of mycorrhizae and the colonization levels of spruce seedlings planted several metres from the edge of the forest were significantly higher than those of seedlings planted further into the cutblocks. The management implications of this study are that there is still an active amount of mycorrhizal fungal inoculum available to seedlings shortly after harvest in the undisturbed organic horizons of the forest floor. This level remains quite high within the rooting zone of the standing timber, but decreases dramatically further into the cutblock.