Magnetic Anomalies on the Tree Trunks |
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| Authors: | Kletetschka Gunther ?ila Vojtěch Wasilewski Peter J |
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| Institution: | (1) NASA Goddard Space Flight Center, Code 691, Greenbelt, Maryland, USA;(2) Howard University, 400 Bryant St, Washington DC, USA;(3) Charles University, Albertov 6, 128 43 Prague 2, Czech Republic |
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| Abstract: | Magnetic measurements of soil and tree bark adjacent to a busy highway revealed a significant variation in the concentration of magnetic particles with distance from the highway. Further more, forest-facing tree-bark contains significantly more magnetic particles than road-facing tree-bark. Magnetic particles were detected both on the bark of the maple trees and in the first centimeter of the soil cover (O/A horizon). Stability of saturation isothermal magnetization (SIRM) and hysteresis parameters of the soil indicates the presence of single domain (SD/PSD) magnetic carriers. Measurements of the tree bark hysteresis parameters and SIRM detect a significant lower coercivity component that we interpret to be an indication of more abundant pseudo-single domain (PSD) type magnetic grains. Magnetic measurements around the perimeters of eight tree trunks reveal magnetic carriers whose distribution is antipodal to the source direction (highway). We interpret our observation by adopting an air circulation model, where suspended PSD/SD particles are carried in the air stream. The air stream from the heavy traffic lowers the amount of moisture on the tree trunk surfaces facing the highway and thus reduces an adhesive potential on this side. Therefore, more particles can stay on the moist side of the trunk protected from the direct airflow. |
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| Keywords: | environment pollution soil Wood iron oxides hysteresis loops |
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