Abstract: With Chinese fir thinnings as raw material,and through measuring the physical-mechanical indices of its compressed wood,observing the variation of its microstructure and using IR analysis,an optimized technique of compressing Chinese fir thinnings was established.The technique was: compression ratio 50%～60%,thickness after compression 20 mm,moisture content before compression 50%,compressing time 20～30 minutes,and hot compressing temperature 180～200 ℃.CH,an environmentally friendly cooking additive,had positive effects on softening the wood.During compressing,only the cells of fast-growing Chinese fir were extruded,their cavity became smaller,while the cell wall was not destroyed.The thickness reversion ratio of compressed wood was 2.68%,and its size stability and mechanical quality were as good as hardwoods (Betula luminifera).

Key words: Chinese fir thinning wood, Compression, Physical-mechanical quality, Microstructure