The Impact of Industrial SO2 Pollution on North Bohemia Conifers
2012
Rydval, Miloš | Wilson, Rob
Conifer forests in the Jizerské Mountains, Czech Republic have experienced widespread and long-lasting effects related to industrial SO₂ pollution. To explore the spatial and temporal impact of this phenomenon on Norway spruce stands, a transect of sites was sampled to the southeast of the Polish coal-fired power station Turów. Tree growth at all sites displayed a significant reduction around 1980, which could not be explained by climate alone. However, by incorporating both climate and SO₂ variables in multiple regression models, the chronology trends could be explained well. The lowest growth rates were found to coincide with the period of greatest atmospheric SO₂ concentrations and the degree of suppression decreased with increasing distance from the power station. The period of growth suppression in a Silver fir site appeared to be more severe and longer in duration than for the spruce, although differing site conditions prevented a direct comparison. Fir trees also appeared to be affected by SO₂ pollution earlier in the twentieth century compared to spruce. Growth of both species, however, did not return to predicted levels following the reduction of pollution levels in the 1990s. A comparison with spruce and fir data from the Bavarian Forest, a region also affected by pollution in the past, revealed a temporal difference in growth suppression, likely related to different timings and loadings of SO₂ emissions between both regions. This study highlights pollution as another potential causal factor for the ‘divergence problem’ and dendroclimatic reconstructions in polluted regions should be developed with caution.
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