Heterobasidion spp presence in young pine plantations in southern Sweden

Sammanfattning: Heterobasidion species cause great economic loss the forest industry in the northern hemisphere. The spread of infection takes two forms, the first is an airborne infection and the second is a vegetative infection from infected root to healthy root. Much research has been done concerning the Heterobasidion pathogen. Little research has however been done on young pine stands with a previous generation of pine. Therefore the presence of Heterobasidion spp in such stands without a known history of infection is unknown. 30 sites, between 4 and 6 years after planting in southern Sweden were sampled. Using a transect and circular plots as proxies for the whole stand. Discs were taken from all dead pine trees found in the transect and 6 randomly taken live trees from two circular plots per stand. Results showed that 6.5% of the live tree samples were infected with Heterobasidion spp, and 6.2% of dead trees sampled were infected. There was no significance in relation to age, density, DBH or height to infection. Although infection presence is a small proportion of these young stands now, with many years until harvest there is much vegetative and airborne infection that could spread through the sites, potentially causing significant damage. The use of control methods such as urea, Rotstop and silvicultural controls could be a way to reduce negative effects of the Heterobasidion spp infection. Especially in a changing climate, it may be prudent to include Heterobasidion spp. controls in forest planning.