Dusting roots of Abiesconcolor and other conifers with Pisolithustinctorius spores at outplanting time proves ineffective

Abstract

Dusting roots of white fir (Abiesconcolor (Gord. & Glend.) Lindl.), shasta red fir (Abiesmagnifica var. shastensis Lemm.), Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco), and ponderosa pine (Pinusponderosa Dougl. ex Laws.) with Pisolithustinctorius (Pers.) Coker & Couch (Pt) spores when outplanted produced no Pt mycorrhizae at the end of the first growing season. In the 3rd year occasional Pt mycorrhizae had formed on white fir. Inoculations reduced seedling survival in some cases. High rate of spore application may have desiccated roots of the true firs; levels of spore application need careful attention. Soil scarification and ripping significantly promoted growth of white fir seedlings compared with scarification alone.