Ecological assessment of phytomass stocks in the zone of alienation and stock of radionuclids

Abstract

It has been established that the main factor causing damage to forests in a large area of the Exclusion Zone is forest fires. Loss of litter stock during combustion is up to 20–30%. 63.0–71.1% of 137Сs stock is stored in litter residues and upper soil horizons. The fires showed a significant increase in the share of the mobile fraction 90Sr in the mineral part of the soil to 39.6–60.8%. In the natural course of migration processes, a significant redistribution of activity in the upper soil horizons could occur in 15–20 years. Therefore, fire-fighting measures are of paramount importance, as fires can significantly change the nature of migration processes of radionuclides. The generalized assessment of phytomass stocks and the stock of radionuclides in the Exclusion Zone testified to the leading role of forest ecosystems in the deposition of radionuclides and prevention of their removal outside the contaminated areas. To date, 47.5 TBq 90Sr has been recorded in wood of forest plantations, which is almost 4% of the total pollution of the Exclusion Zone and this share will continue to grow. A system of ecological and forestry care for forest plantations in the conditions of the Exclusion Zone has been developed. It provides for three levels of intervention — normal, limited, protected (in the future). Its implementation took place during forest management works in 1996 and 2006, which provided control over the radioecological and forestry situation.