A study of root extension in surface soils of a natural stand of longleaf pine and turkey oak was carried out in the sandhills of North Carolina. I-131 was introduced to soil at selected spots, absorbed by roots, and translocated to trees through vascular elements. Trunks of trees in the vicinity were monitored for gamma radiation to determine which trees had root connections with the soil volume containing I-131. Radioactivity was detected in pine stems as far as 55.1 feet from plot center and in oak stems out to 48.7 feet. All pine trees monitored within a radius of 17 feet from plot center showed contact with the isotope source, while I-131 was detected in all oaks within 15 feet. Factors most closely related to distance of root extension were elevation and tree age in the case of longleaf pine while elevation and tree age were important in the case of turkev oak.
Document Type: Journal Article
Faculty Member, The University of Vermont