Dendrochronological research of Scots pine (Pinus sylvestris L.) radial growth in vicinity of industrial pollution

The aim of this research is to investigate changes in the annual radial increment of Scots pine (Pinus sylvestris L.) in the vicinity of intensive (3–10 km) and moderate (11–20 km) industrial pollution during different growth periods (growth promotion, inhibition, and recovery). Low level of emission was beneficial for tree growth during the growth promotion period, and the annual radial increment in the zones of intensive and moderate pollution increased by approximately 15–25% and 10%, respectively. Severe loss was reported to forests during the growth inhibition period when nitrogen and sulphur dioxide emissions were 37–40 thousand (thou.) tons per year. About 40–45% tree radial increment loss was observed in the stands closest to the pollution source, and 15–20% loss was observed for the most distant stands. The stabilization of radial growth decrease and the beginning of recovery of damaged stands began in 1988–1992, when the annual amount of industrial emissions and environmental pollution were considerably reduced. The stabilization of radial growth and the initiation of recovery after pollution reduction were high for the most damaged stands. Their radial increment was stable and close to that of the control stands in 2000–2011. Stands with less damage growing further from the pollution source were recovered earlier, and their radial increment stabilized near the control increment in 1995–1999. The results of linear regression analysis demonstrated that the impact of pollution is different for stands growing at different distances from the plant, and the impact decreases with distance (R² = 0.78 and R² = 0.75, respectively; p < 0.05).