| Abstract: | On the regeneration and infection of roots of Douglas fir (Pseudotsuga menziesii Mirb.] Franco) by fungi present in the soil. 167 roots in 4 stands were severed 40–60 cm from the base of the tree. At the proximal cut ends of the thick roots of the 40 years old trees on loamy sand, either replacement roots or callous tissue were formed (only a small percentage of those roots was invaded by rot causing Basidiomycetes), or no new roots and no callus were formed and root rot fungi (Fomes annosus, Coniophora puteana, Resinicium bicolor) had invaded the root sections from the soil. On the root sections of the 35 and 55 years old Douglas firs on sand, with the exception of 2 roots, neither replacement roots nor callus were formed; Fomes and Coniophora had invaded the thicker roots of the older trees from the soil. |
