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Eight species were used for this experiment:Taiwan spruce , White spruce (USA), Elka spruce (USSR), Chinese hemlock, Western hemlock, Taiwan acacia, Chinese guger-tree, Rubber wood, to determine the effects of the dimensional stability of acetylated wood and its decay resistance. The results obtained by this experiment may be summarized as follow : 1.The anti- shrinkage efficiency (ASE) in radial direction of eight acetylated woods were more than 77%, and all of the ASE in tangential direction of eight acetylated woods were more than 81%. All of the acetylated woods showed higher dimensional stability. 2.The water excluding efficiency (WEE) of all tested species were relatively lower in the efficiency. Becaus the acetyl groups would reduce the water absorption ofcell wall only, therefore WEE showed the range from 8-29%. 3.The hygroscopicity related to the Equilibrium moisture con- tent of eight acetylated woods were 6.2-9.0%, on the con- traryuntreated woods were 15.4-19.8% at 40℃ 90%R.H. con- dition for 12 days. The result showed acetylation treatment couldgreatly reduce the hygroscopicity of wood. 4.The decay resistance of eight species of acetylated woods related to residual of weight properties were 92%, while the untreated woods were 56-85% only for during 120 days white-rot fungi test. Resdual of compressive strength para- llel to grain (MOR) of acetylated woods were more than 84% , while the untreated woods were 33-77% only.The residual weight of eight acetylated woods were more than 89%, while the untreated woods were 43-85% only for during 120 days brown-rot fungi test. The resdual MOR of acetylated woods were more than 73%, while the untreated woods were 5-22% only. Particularly soft woods were very conspicuous in this test.
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