Environmental Effect Studies on a Forest Ecosystem in Germany

—Transport of Chernobyl-derived radiocesium in a forest—

Abstract

Long-term acid deposition on a forest ecosystem can have serious impacts on many physicochemical processes in the soil. Since 1984 extensive studies have been carried out in the “Höglwald”, an old Norway spruce stand near Munich, Germany. In 1986 a variety of radionuclides were deposited in the canopy and on the forest floor of the Höglwald following the reactor accident at Chernobyl. The amount of ₁₃₇Cs from Chernobyl was about 10 times larger than that present in the soil before Chernobyl. Six experimental plots were established in order to study the potential disturbances caused by artificial acid irrigation and compensative liming. Using these fields, investigations on the interception and retention of radionuclides by a coniferous woodland have been done together with the deposition and vertical migration of the radionuclides in the forest. One of the most important results obtained was that ₁₃₄Cs deposition velocity in the spruce stand was as high as 5.5mm/s, and thus higher by a factor of 10 than the corresponding value for the grassland. By evaluating the depth profiles of the Chernobyl-derived ₁₃₇Cs in the soil with a compartment model. The fixation of radiocesium in the forest soil was found to be a rather slow process.