Afforestation on the radiation contaminated territory

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I. Trohymchuk

Abstract

Introduction. A significant amount of radionuclides which is accumulated in the forestry after Chornobyl nuclear power station disaster caused necessity of solving such problems as organizational, economical, forestry, ecological and social which human has never faced before.

Purpose. Detecting of regularity of radionuclides behavior in forest ecosystems and studying features of afforestation process on the radionuclides contaminated territory.

Results. Detecting of regularities of radionuclides migration in the forest ecosystems is rather complicated and time-consuming research process. We selected three kinds of wooden circle with the aim of studying of137Cs accumulation condition and advisability of their stocking as industrial raw materials: English Oak (Quercus robur L.), Silver Birch (Bеtula pendula), Scots Pine (Pinus sylvestris L.). Obtained data demonstrates that the biggest part of total activity of 137Cs of ecosystem (76,48%) is concentrated in the soil, including 18,09% – in the forest bedding and 58,39% – in mineral layer of soil. Accordingly, components of above-ground phytomass coenosis retained 23,52% of gross margin of 137Cs of forest ecosystem.

Due to considerable phytomass the part of wooden circle in contributing of 137Cs in the ecosystem is defining among components of phytocoenosis and it is – 13,71%. Based on the results of radiological research the contents of radionuclides 137Cs in English Oak (Quercus robur L.) is in average 1786 Bq/kg; Scots Pine (Pinus sylvestris L.) 2394 Bq/kg; Silver Birch (Bеtula pendula) – 1590 Bq/kg.

Originality. Comparative analysis of obtained data indicates that part of wood in retaining of 137Cs of wooden mass generally is much less in comparison with phytomass distribution. In return the part of physiologically active materials and organs (one-year shoots, one-year needles and inner bark with phloem) is much bigger, moreover, mainly due to higher specific activity of radionuclides in them.

Conclusion. The bush plants and herbaceous plants and also mushrooms demonstrate the highest degree of contamination which has the main mass of root system in upper (5-20 cm) soil layer where up to 90 % of radionuclides are concentrated. General decreasing of contamination level of different components of forest ecosystem is observed due to partial decay of 137Cs and 90Sr  (only some parts are exclusion in which the content of 137Cs і 90Sr in many components increased significantly as a result of flood or fire).

The ways of filtering of forest ecosystems from radionuclides are versatile – starting from regulation of radionuclides circulation with fertilization to using of forest own unique features as to fixating 137Cs and 90Sr or transferring them to into insoluble, non-changing forms.

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References

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