Characteristics of AC conductivity of tree for detecting tree clones

Abstract

In this paper we propose a new method, ‘bioelectrical impedance method’ to distinguish clonal plant in the forest community. Bioelectrical impedance methods have rarely used in forestry and forest ecology except a case of water status measurement in tree, though it has been applied in many other fields especially in medical uses, such as BMI (body mass index) measurement. The internal soil impedance, internal tree impedance and grounding impedance of clonal tree were measured by using an LCR meter. The impedance of internal soil was decreased as VWC of soil increased. Internal tree impedance and grounding impedance showed similar pattern to the soil in frequency response. Comparing the three parameters, we found that the orders of them were as follows; internal soil impedance < grounding impedance < internal trunk impedance. The AC signal was transferred between trunks connected underground though soil impedance and grounding impedance were smaller than internal tree impedance. AC signal was transferred clearly at relatively lower frequency and the frequency from 5 kHz to 10 kHz was favorable to the measurement. Those results suggested that it was possible to distinguish clonal tree ramets from other timbers without any destruction by using AC signals with relatively low voltage.