The application of the tree-ring chronologies in assessing ecological requirements of Metasequoia glyptostroboides growing in southern Poland

Metasequoia glyptostroboides is considered to be a species highly resistant to harmful environmental factors. For this reason it has been introduced to the cities. The climate of Krakow differs from that in its natural range in China. The research was focused on 40-year-old trees, planted in Kraków on fertile alluvial soils with a low level of ground water, in the vicinity of the steelworks. During the period of the highest level of air pollution in the 1970s and 1980s, the radial increment of investigated trees showed an increasing trend. At the end of the 1980s, when the emissions were reduced, a decreasing trend in radial growth was recorded. Throughout the entire period of their life the investi-gated trees have shown high homogeneity of short-term growth reactions. The sensitivity chronology of the trees was characterized by a high representativeness and a strong high-frequency signal. This may indicate that the investigated trees have shown a large sensitivity to climatic factors.

The positive effect on the radial growth of Metasequoia had a cold September in the previous year, and also a cold January, April and May in the year of ring formation. Positive impact on the growth of trees had also the high precipitation occurring in April and August, as well as high air humidity in the spring of the year of ring formation. In the period 1974–2011 fifteen signature years were found. The analysis of the climatic conditions in these years confirms the results of the statistical analyses.