Table 3.
Change of density and mass loss of the three wood species after heat treatment

Content	Royal paulownia		Suwon silver poplar		Korean red pine
	Density (g/cm3)	Mass loss (%)	Density (g/cm3)	Mass loss (%)	Density (g/cm3)	Mass loss (%)
	Control	0.26±0.02	-	0.55±0.04	-	0.50±0.06	-
160°C	0.26±0.01	1.8±0.27	0.53±0.03	1.5±0.14	0.49±0.05	2.2±0.32
180°C	0.26±0.01	8.6±0.27	0.51±0.04	2.8±0.18	0.47±0.04	3.5±0.25
200°C	0.25±0.02	11.4±0.29	0.49±0.01	5.8±0.46	0.45±0.03	6.4±0.30
220°C	0.23±0.04	15.0±0.76	0.49±0.04	13.6±1.62	0.45±0.04	9.2±0.54