The effect of galactan content on the mechano-sorptive strain in loblolly pine

Abstract Mechano-sorptive (MS) strains were measured in torsion on eight loblolly pine specimens as a function of galactan content. The strains were generated by an increase of environmental humidity from 38% to 84% and were measured during an anticlockwise and a clockwise loading scheme that caused the specimen to recover its original dimensions at the end of the test. The magnitude of the MS strains was found to be independent of galactan concentration. The specimens with high and low galactan contents had different MS strains but the average of the measured data was the same. The number of observations (eight) was too small for a reliable statistical analysis to identify the regressors that are the main sources of the strain variations. The cell structure of the specimens was visualised by X-ray tomography.