Comparative Investigation of Different Methods for Measuring the Dielectric Constant of Tree Constituents

Abstract

The dielectric constant of vegetation depends on the amount of "free" and "bound" water and therefore is a measure of the plant water status. Dielectric constants on the other hand are important input parameters for backscatter models. Existing methods for measuring the dielectric constants can be separated into two major categories: direct measurements using special RF probes, and indirect measurements of the volumetric water content and conversion into dielectric constants using semi- empirical relationships. This paper presents a comparison of the different methods and a detailed analysis of the achievable accuracies with the aim to develop most efficient methods for measuring dielectric constants of tree parts.