Treatment of Picea abies and Pinus sylvestris Stumps with Urea and Phlebiopsis gigantea for Control of Heterobasidion

Heterobasidion spp. root rot causes severe damage to forests throughout the northern temperate zone. In order to prevent Heterobasidion infection in summertime cuttings, stumps can be treated with urea or Phlebiopsis gigantea. In this study, the consumption of stump treatment materials and the quality of stump treatment work were investigated. A total of 46 harvesters were examined in May-November 2016 in Finland. The average stem size of softwood removal and softwood removal per hectare explained the consumption of stump treatment material. The quality of stump treatment work was good in the study. The best coverage was achieved with the stumps of 20-39 cm diameter at stump height (d(0)). It can be recommended that the harvester operator self-monitors and actively controls his/her treatment result in cutting work and sets the stump treatment equipment in a harvester if needed. The results also suggested that when cutting mostly small-and medium-diameter (d(0) <= 39 cm) conifers, the stump treatment guide bars with relatively few (<18) open holes are used, and at the harvesting sites of large-diameter trees, the guide bars with a relatively great (> 7) number of open holes are applied.