The untreated Swietenia microphylla wood has high coefficient of shrinkage and swelling, the shrinkage rate in the tangential direction is 6.85 percent, the shrinkage rate in the radial direction is 4.33 percent
the swelling rate in the tangential direction is 7.48 percent, the swelling rate in the radial direction is 5.04 percent. When wood sample is treated by PEG-600, the coefficient of shrinkage and swelling in the tangential and radial direction greatly reduced: in the tangential direction is between 3.3 - 5 percent, in the radial direction is between 2.7 - 3 percent. Detennination of characteristics of treated wood: anti-swelling efficient (ASE) from 17.32 percent to 54.55 percent
the weight percent gained after PEG treating is from 8.74 percent to 27.73 percent. The technological parameters of treating Swietenia microphylla wood by PEG-600 were identified: T= 48 - 52°C, r = 8 - 9, N = 20 - 30 percent.