M. Bendzhellgren et J. Stenlid, EFFECTS OF CLEAR-CUTTING, THINNING, AND WOOD MOISTURE-CONTENT ON THE SUSCEPTIBILITY OF NORWAY SPRUCE STUMPS TO HETEROBASIDION-ANNOSUM, Canadian journal of forest research (Print), 28(5), 1998, pp. 759-765
The effects of clear-cutting and thinning as well as heartwood and sap
wood moisture content on spore infection by Heterobasidion annosum (Fr
.) Bref. were investigated in summer cuttings in southern and central
Sweden. At five sites, 20-100 stumps in clear-cut, thinned, and precom
mercially thinned stands of Norway spruce (Picea abies (L.) Karat.):we
re created and left for natural spore infection. An additional 20 stum
ps per stump type and site were artificially inoculated with conidiosp
ores of H. annosum. The probability of natural infection was 0.73 and
0.53 for stumps in thinned and clear-cut stands, respectively. Almost
all (95%) of the artificially inoculated stumps in thinned and clear-c
ut stands became colonized, and no differences due to stump type were
found. The probability of infection of stumps in precommercially thinn
ed stands was lower than for the other stump types of both naturally a
nd artificially inoculated stumps. The proportion of colonized sapwood
was reduced with increasing moisture content. Stump colonization seem
ed unaffected by temperature, even though stump temperatures exceeded
40 degrees C for 2 h at one site.