Root and Butt Rot in First Generation of Norway Spruce Affected by Spacing and Thinning : Root and Butt Rots

Uppsala

International Union of Forest Research Organizations, Swedish University of Agricultural Sciences

1994

S. 642-645

14 Lit. Ang.

Bandaufführung

13462

73833

High frequency of root and butt rot in Norway spruce constitutes a major source of concern for Nordic forestry. Earlier findings have indicated effects of spacing and thinning upon the development of rot. Recently some mature spruce stands in Norway were analysed by the time of clear-cutting. These stands were planted on non-forested land about fifty years ago, under three different spacings and through the years subjected to different thinning programmes. Root and butt rot occurred in high frequencies in narrowly spaced stands subjected to early and strong thinnings, while low frequencies were found in widely spaced stands subjected to weak thinnings performed late in the rotation period. These results correspond to earlier findings in similar spacing and thinning fiels tests, and comply with Nordic experiences. Heterobasidion annosum was the most frequent rot organism. Wound rot, mainly caused by Stereum sanguinoletum, was found in surprisingly high frequencies, as a result of wounding made during forest operations. Practical means to reduce infections are strongly needed.