Exploration of seasonal moisture variation in standing loblolly and slash pine using time domain reflectometry

Abstract

Seasonal variation in the moisture content (MC) of standing trees can have a significant impact on wood (and when harvested) log weight; however, its variation is poorly understood owing to the destructive nature of sampling methodologies. To improve our understanding of temporal moisture variation, low cost systems that continuously monitor MC of standing trees are required. Time domain reflectometry (TDR) was explored as an option to estimate standing tree MC. TDR data was collected from ten loblolly and ten slash pine trees growing on the Lower Coastal Plain of Florida and ten loblolly pine from the Piedmont of Georgia on a weekly basis for approximately 1 year. Site specific calibrations were used to predict MC, but owing to a pronounced wound response it was not possible to accurately track temporal changes in whole-tree MC. If calibrations more oriented toward living trees can be obtained, it may be possible to use TDR to monitor temporal changes in standing tree MC.