Et. Choong et al., Effect of steaming and hot-water soaking on extractive distribution and moisture diffusivity in southern pine during drying, WOOD FIB SC, 31(2), 1999, pp. 143-150
Samples of southern pine sapwood and heartwood were treated five different
ways: steaming in the saturated condition for 1 h and 5 h, respectively, st
eaming at a moisture content near the fiber saturation point (FSP) for 1 h,
hot-water soaking for 10 h, and steaming near 95% relative humidity at an
equilibrium moisture content (EMC) slightly below the FSP for 1 h at 100 de
grees C. The samples were dried from near saturation condition to an EMC sl
ightly below the FSP, and then to final 12% EMC. The results indicate that
the amount of extractives removed tended to be evenly distributed along the
how direction before drying and after drying to near FSP, which suggests t
hat extractives move with water in wood in response to moisture gradient du
ring drying. Hot-water soaking and prolonged steaming increased the moistur
e diffusivities above and below the FSP. The variation in diffusion coeffic
ient was partially due to changes in the extractive distribution profile.