Change in moisture content (MC) of each OPT section
prepared from middle part of trunk was examined during 120
days of storage as shown in Fig. 2. Immediately after logging,
MCs of Part A, B and C were 78, 75 and 67%, respectively.
Compared to ordinary wood timber, the MC of OPT is extremely
high, as MC of wood is normally ranging between 40 and 50%.
Part A, the most inner of the trunk, contains the highest
moisture among the three sections, and the MC becomes lower
toward the outer section that is Part C. The trunk consists of
fibrous vascular bundles and powdery parenchyma. The
parenchyma seems to hold more moisture than the vascular
bundles. The difference in MC between the sections may be
attributed to the ratio of parenchyma and vascular bundles. In
fact we observed more parenchyma in the inner section.
During the 120-day storage, the MC went slightly lower for all
sections. The decrease in MC being marginal (less than 10%),
evaporation of moisture from the stored logs was presumably
prevented by hard outer bark of the trunk.