Spatial and temporal variation of the microwave dielectric properties of loblolly pine trunks

The dielectric properties of loblolly pine trunks are found to be seasonally and diurnally variant. In addition, the dielectric constant is found to vary both with depth into the trunk for different tissue regions (i.e., phloem, cambial zone, and xylem) and also vertically for the same region. These variances are systematic and cannot be ascribed to sensor calibration or sampling biases alone. The diurnal dielectric measurements are found to be partially correlated to canopy layer physiologic observations such as transpiration, stomatal conductance, and xylem water potential. Experiments were conducted in the Duke University Research Forest west of Durham, NC.

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Author Norman L. Christensen Environmental Sciences and Policy