Seasoning schedule establishment for Gmelina
1999
Delgado, T. (Philippines Univ. Los Banos, College, Laguna (Philippines). Coll. of Forestry and Natural Resources)
Wood characteristics of Gmelina was studied to determine the proper drying or seasoning of the wood. The study included the evaluation of the anatomical features, its specific gravity, shrinkage at radial and tangential faces, re-absorption rates, natural drying, low temperature drying and moderately high temperature drying of 2.25-in thick gmelina lumber measuring 2 x 5 in. Gmelina was classified as a low specific gravity species. The shrinkage value of Gmelina indicated that the tangential shrinkage was 1.5 to 2 times higher than the radial shrinkage. This was based on results from green to 20 percent, 15 percent, 10 percent, and 0 percent moisture content (MC). Maximum radial shrinkage was 2.9 percent, and the maximum tangential shrinkage was 4.9 percent, with maximum volumetric shrinkage of 8.74 percent. Results of the anatomical structure evaluation of Gmelina in three sections showed the presence of tyloses or sac-like membranes on some of its pores. Tyloses blocked the movement of water in wood. Natural air drying and forced air drying to fiber saturation point (FSP) before kiln drying resulted in the substantial reduction in drying time from 90 days to 56 days with 60 percent average recovery. This reduced the energy requirements and costs of drying. Low temperature (100-136 deg F) drying from FSP took 31 days to attain 12 percent MC with a 65 percent production efficiency for export quality, and 22 percent meeting MC levels for local use.Only 13 percent needed redrying. Moderately high temperature (150-180 deg F) drying from FSP took only 28 days to attain 12 percent MC with 75 percent production efficiency for export quality and 25 percent meeting MC levels for local use. The dryer output efficiency was also improved with very low reabsorption rate
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