Home – Home – Jornals – Siberian Journal of Forest Science 2025 number 4

First registered in Perm Krai in 2022, the invasive four-eyed fir bark beetle Polygraphus proximus has expanded its secondary range to almost 8,000 ha on the territory of 10 forestry districts of the region by the beginning of 2025. At the same time, the phytosanitary quarantine zone has grown to 1 million hectares. For dendrochronologic dating of tree mortality on the sites where initial foci was documented, the samples from five sites were analyzed: in Dobryanskoe forestry (2 sites) and in urban forests of the city of Perm (3 sites). In total, 131 tree-ring rows for 118 trees killed by the bark beetle and 60 rows for 40 live trees were used to construct a master chronology. Dating the dieback of the trees which appeared to have the earliest infestation signs of the beetle allowed us to define time when four-eyed fir bark beetle could first occur in Perm Krai. The earliest tree dieback was observed on the two sites in Dobryanskoe forestry (in 2011 and 2014 respectively). The invader penetrated the city of Perm significantly later: fir trees started to die in 2018, 2021, and 2022 on the studied city sites. Bearing in mind that the beetle requires at least 2-3 years to settle down in a new region, it can be assumed that four-eyed fir bark beetle arrived to Perm Krai no later than 2009.