Changes in basal area increments and δ¹⁵N of Scots pine growing near industrial steelworks in Dąbrowa Górnicza, Poland

In this study, we present evidence using basal area increments (BAI) and ¹⁵N/¹⁴N nitrogen isotopic composition of Pirns sylvestris from sites near the industrial area in Dąbrowa Górnicza (Poland) to assess potential effects of pollution on tree growth and physiology. Changes in BAI reveal a marked long-term decline in stem growth during peak industrial pollution in the 1960s followed by a distinct subsequent increase after the mid 1980s. Coinciding with the earlier period of growth suppression, we also found a decrease in covariance of growth increments among trees and a weakening of the climatic signal in pine tree-ring chronologies followed by a change related to summer drought sensitivity since the 2000s. The ¹⁵N/¹⁴N ratios reveal distinct evidence of emissions from steel manufacturing since 1978 including a change in δ¹⁵N values from -10 to -4 %o in the polluted Scots pines. The results of this study show that there is a strong inverse correlation between tree-ring δ¹⁵N values and the nearby steelwork production rate coinciding with changes in growth rates and covariance among trees.