A case study of possible relationships between air pollution and tree rings in the northwestern Czech Republic

Joseph Pinto1 and Ivan Benes2

This is a case study illustrating the possible effects of severe air pollution and subsequent recovery on a Canadian Silver Spruce growing in the Northwestern Czech Republic. Differences in the width of tree rings coincide with different air pollution regimes. The width of the rings can be characterized by three distinct regimes: an early growth stage (lasting ~25 years); an intermediate stage consisting of extremely narrow rings (lasting ~ 30 years) and a final stage with broad rings (lasting ~20 years). During the middle stage, the area was subjected to high levels of air pollution (mainly SO2 and PM). In the middle of the 1990s, effective pollution controls were instituted, resulting in rapid declines in levels of SO2 and PM.

Periodic inspection of the tree during the intermediate period of heavy pollution revealed little or no insect or fungal parasites and no cones. Spruce aphids appeared only during the past several years resulting in severe loss of needles near the end of the tree’s expected lifespan. This observation can be readily explained if insect and fungal pests were also strongly affected by the high levels of air pollution (54 < SO2 < 140 μg/m3 annual average) found during the middle stage and their population recovered during the years characterized by much lower pollution (SO2 < 15 μg/m3 annual average). Of course, further studies that rely on isotopic analyses (e.g.) are needed to more clearly make the link between tree growth, altered physiology and air pollution induced stress.

The views expressed are those of the authors and do not necessarily represent the views or policies of the U.S. Environmental Protection Agency.

 

1US EPA/NCEA, pinto.joseph@epa.gov
2Zdravotni Ustav - Usti nad labem, ibenes@volny.cz