Prompt Transfers of Cesium‐137 to the Soils of a Tagged Liriodendron Forest
1967
Waller, H. D. | Olson, J. S.
An inventory of total Cs¹ ³ ⁷ distribution in a 500—m² tagged tulip poplar (Liriodendron tulipifera) forest at the Oak Ridge National Laboratory showed transfer from trees to soil during the first growing season. About one—third of the maximum amount of radiocesium found in the tree canopy during June was transferred to the forest floor and soil; the remainder moved back into woody tissue (stem and roots) before leaf fall. Losses of radiocesium from the foilage and stems into the plot area through litterfall (55 μc/m²) and rain leaching (13 μc/m²) accounted for almost 8% (68 μc/m2) of total Cs¹ ³ ⁷ (934 μc/m²) introduced into tree boles. However, soil (including roots) and litter sampling at the end of the growing season indicated a much larger quantity (414 μc/m² or 45% of initial input) already in the surface 30—cm layer of mineral soil. Of the total Cs¹ ³ ⁷ activity found within the mineral soil layer, about half can be physically associated with the tagged trees removal of roots from soil samples and cumulative measurement of surface income at time of soil collection. Much of the remainder can be accounted for by contact exchange, root exudation, root death, and leaching of roots by soil solution.
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