Effect of steaming and hot-water soaking on extractive distribution and moisture diffusivity in southern pine during drying

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.