Occurrence of Heterobasidion annosum in middle-aged Scots pine stands in Latvia

Abstract

Root rot monitoring in Scots pine (Pinus sylvestris) stands can signal potential risks for pine health in the coming decades. However, in Latvia, the current inventory data on root rot fungi, especially Heterobasidion annosum infection, in middle-aged Scots pine stands are limited. Therefore, this study assessed the presence of H. annosum across Latvia, in a total of 153 managed 40–60-year-old Scots pine stands. The pathogen was confirmed in 39% of all surveyed stands by observing its basidiomata and isolating it from wood samples. Occurrence of H. annosum was highly stochastic and was not related to forest type, stand age or geographical region (p > 0.05). These findings indicate a high rate of Heterobasidion root rot infection in Latvian middle-aged Scots pine stands and the need for targeted forest management strategies to limit the pathogen's effects.

Keywords: Heterobasidion root rot, forest pathogens, Pinus sylvestris, root rot fungi, forest health survey, Heterobasidion monitoring