Study on the changes in surface characteristics of Populus tomentosa due to thermo-hydro-process

Journal of Wood Science

Official Journal of the Japan Wood Research Society

Table 3 Average values of surface characteristics of color values and roughness parameters on poplar surface before (untreated) and after THM treatment

samples	Density (g/cm³)	Color values				Roughness parameters (µm)
samples	Density (g/cm³)	L*	a*	b*	∆E ^*	Ra	Rt	Rz
Untreated	0.39	77.56 (0.66)^A	2.93 (0.48)^D	17.30 (0.78)^B	–	4.72 (0.47)^A	45.82 (0.92)^A	33.62 (1.37)^A
CR50	0.75	73.07 (1.42)^B	3.26 (0.10)^D	19.74 (0.51)^A	5.27 (0.93)^D	2.11 (0.11)^B	33.69 (1.21)^B	28.21 (0.93)^B
CR60	0.90	66.80 (1.64)^C	5.30 (1.36)^C	19.07 (1.68)^A	11.20 (1.54)^C	1.85 (0.07) ^C	27.87 (1.06)^C	24.43 (0.95)^C
CR70	1.07	46.05 (2.07)^D	9.05 (0.66)^A	16.19 (0.77)^B	32.07 (2.12)^B	1.54 (0.06)^D	21.19 (1.09)^D	19.47 (0.80)^D
CR75	1.30	28.45 (1.19)^E	6.91 (0.29)^B	7.53 (0.75)^C	50.23 (1.17)^A	1.02 (0.06)^E	16.48 (0.62)^E	17.12 (0.64)^E

Values in parenthesis are standard deviations. For each parameter, average values with different letters in the same column indicate a significant difference at p < 0.05 [analysis of variance (ANOVA), followed by Duncan’s multiple range test]
THM thermo-hydro-mechanical, CR compression ratio, Ra mean roughness, Rt maximum height of the profile, Rz mean peak-to-valley height