Tree Health of Larix sibirica Ledeb. in the Railway Impact Zone on Kola Peninsula

The environmental conditions on Kola Peninsula are affected by industry and transport with substantial consequences for tree health. The research aimed to assess the tree health of Larix sibirica in the railway impact zone in four settlements: Apatity, Murmansk, Polyarnye Zori, and Olenegorsk. The methodology included determining the state of plants, a comparative analysis of the heavy metals’ content in soil and needles, and seed regeneration analysis. In results, the middle-weakened specimens were shown to dominate the forecourt areas in all locations excluding Murmansk, where only the highly weakened plants were observed. Soil survey revealed pollution by Ni, Cu and Zn, which contents were 2 to 6 times above the health thresholds. The content of Ni and Cu in needles was also 3 to 8 times higher compared to the natural references. The extremely high Fe contents in needles ranging from 1.87 g kg⁻¹ in Murmansk to 4.28 g kg⁻¹ in Apatity also witnesses the impact of railway transport. At the same time chloroses or any other damage to the assimilating apparatus were not found in the observed Larix sibirica trees. It was also shown that the ability to natural regeneration in Larix sibirica was preserved. Laboratory seed germination rates ranged from 4% (Murmansk) to 31% (Polyarnye Zori). No viable seeds were found in Olenegorsk. Based on the research outcomes, Larix sibirica can be recommended for introduction to the protective plantings along the railway track and used for greening train stations due to high resistance to pollution and long lifetime.