%0 Research article
%T Control efficacy of stump treatment and influence of stump height on natural spore infection by Heterobasidion spp. of precommercial thinning stumps of Norway spruce and birch
%A Gunulf, Anna
%A Mc Carthy, Rebecka
%A Rönnberg, Jonas
%D 2012
%J Silva Fennica
%V 46
%N 5
%R doi:10.14214/sf.917
%U https://silvafennica.fi/article/917
%X An alternative precommercial thinning technique results in trees being  cut higher up the stem compared to the normal method using a brush saw.  The aims of this study were to investigate if primary infection of  Heterobasidion spp. on precommercial thinning stumps of Norway spruce  and birch is influenced by stump height and to test the control efficacy  of stump treatment with Phlebiopsis gigantea on precommercial thinning  stumps of Norway spruce. Small Norway spruce and birch trees were felled  on five sites in southern Sweden and their stumps subjected to natural  spore infection. For each species, two treatments of stump height were  created: 15 and 100 cm. Half of the Norway spruce stumps were treated  with P. gigantea. After two months, 896 stumps were sampled and  infection by Heterobasidion spp. was quantified. The height of stumps  did not significantly influence infection frequency or size of infection  on either tree species. Untreated Norway spruce stumps had an infection  frequency of 55% while 31% of the treated stumps were infected. The  control efficacy of stump treatment in terms of reduced relative  infected area was 61–65%. The area occupied by Heterobasidion spp. on  birch stumps was generally small, on average 0.4 cm2 per infected stump,  although 15% of the stumps were infected. The risk of primary infection  in Norway spruce dominated stands should be considered when  precommercial thinning is conducted but the control efficacy and economy  of stump treatment warrants further investigation before practical  recommendations can be made.