Impact of air pollution on morphological parameters of conifers in an area of soil shale mining and processing
2000
Ots, K. (Estonian Agricultural Univ., Tartu (Estonia). Forest Research Inst.)
Air pollutants (oil shale fly ash, gases, organic compounds) emitted by the oil shale industry in Kohtla-Jaerve, North-East Estonia, have caused changes in the growth conditions of forest ecosystems. Compared with the period before 1990 the pollution load in the area investigated has fallen drastically; however, this has not resulted in an essential improvement in growth conditions of trees. Morphological analysis of 80-year-old Picea abies (L.) Karst. and Pinus sylvestris L. growing on sample plots (6) in the polluted area and in the control area showed that air pollution has had a temporally and spatially variable effect on the parameters characterising the state of trees: length growth, weight and dry matter content needles and shoots, density of needles on shoots and radial increment of trees. The length growth of Scots pine needles and shoots proved to be one most suitable parameters indicating the influence of air pollution, although not in all sample plots investigated. The results for fresh and dry weight of needles revealed great differences between sample plots. The biomass of the shoots of Norway spruce was notably greater in the immediate vicinity of Kohtla-Jaerve than in the control. The Scots pines and Norway spruces whose shoots showed inhibited length growth had greater density of needles on shoots with difference from the control being respectively up to 33 per cent and 16 per cent. The effect on the radial increment of Norway spruces was especially strong in the immediate vicinity of pollution sources but it fell rapidly with distance from them
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