Reduction determinants of Scots pine tree-ring width in the vicinity of Puławy industrial plants (central-eastern Poland)

Scots pine (Pinus sylvestris L.) is a tree species that reacts to meteorological conditions, industrial pollution and groundwater level. The aims of this study were to evaluate reductions and increases in Scots pine tree-ring widths (VTRW) as compared to reference sequences for sites in two types of forest habitat found in the vicinity of the chemical plant complex in Puławy, located in central-eastern Poland, and to determine the relationship between VTRW, climate and anthropogenic factors. A considerable reduction in tree-ring widths compared with reference sites was found for sites affected by chemical plant emissions from the end of the 1960s, i.e. right after the start of the Puławy industrial plants, to the beginning of the 1990s (implementation of new technologies). This period of reduction in tree-ring width lasted longer and was greater in magnitude in the pure Scots pine stands studied within a coniferous mixed forest habitat. Furthermore, the reduction in Scots pine tree-ring width was largely dependent on below-average air temperature in the period from December of the year preceding ring formation until January of the current year and above-average total precipitation from June until August above-average SO2, NH3 and NOx emissions and above-average surface and underground water withdrawals from company intakes. The influence of weather on VTRW was weakened by anthropogenic factors, which affected the quality of the local natural environment. Therefore, Scots pine tree-ring width may be used to evaluate the state of the natural environment and threats it is facing in areas with high levels of industrial pollution including, for example, SO2, NH3 and NOx. Keywords: temperature and precipitation conditions, air pollution, tree-ring width, forest research area, dendroecological studies, Central Europe, Pinus sylvestris L.