Among the construction materials which are used by people wood holds a special place because of its impressive range of attractive properties, including low thermal extension, low density and high enough mechanical strength (Bektha and Niemz 2003). In recent years, there has been a rapid increase in the application of chemicals to wooden materials in order to improve their physical, mechanical, biological, and fi re properties (Yalinkilic et al. 1999, Chao and Lee 2003, Brelid et al. 2000, Wen Yu 1997).