Heterobasidion annosum: Development of Butt Rot following Thinning in two young First Rotation Stands of Norway Spruce

• Published in: Forestry (London) 1988, Vol.61 (4), p.339-347
• Main Authors: PRATT, J. E., GREIG, B. J. W.
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Fungal plant pathogens; Pathology, epidemiology, host-fungus relationships. Damages, economic importance; Phytopathology. Animal pests. Plant and forest protection
• ISSN: 0015-752X; 1464-3626
• DOI: 10.1093/forestry/61.4.339

SUMMARY Severe butt rot caused by Heterobasidion annosum (Fomes annosus) developed in two stands of first rotation Norway spruce on old agricultural land within 11 years of first thinning. At Site I (Devon), 11 per cent of thinning stumps and 23 per cent of clear felled stumps were found to be decayed when examined soon after the crop was felled at age 37 years. It is estimated that between 4.4 per cent and 6.6 per cent of potential volume was lost on clear felling. Significant butt rot had also developed in a 33-year-old stand of Norway spruce in Site II (Aberdeenshire) 11 years after a Scots pine nurse crop was removed. Here, the disease was found to be widespread on an area of 2 ha, and 73 per cent of trees had butt rot. Decay extended 3 m up the stems, and occupied significant areas of the butt. In both cases, the presence of butt rot in the crops led to premature clear felling, which resulted in additional loss of potential revenue. It seems most likely that the disease became established following infection of thinning stumps by airborne spores of the fungus: at Site I, the thinning stumps were not protected whilst at Site II it would appear that a chemical or biological treatment applied to the pine stumps failed. The subsequent rapid development of the disease was due, in part, to a variety of environmental and edaphic factors.