Relationship between the xylem maturation process based on radial variations in wood properties and radial growth increments of stems in a fast-growing tree species, Liriodendron tulipifera

Journal of Wood Science

Official Journal of the Japan Wood Research Society

Table 5 Estimated values of the fixed and random effects of the selected models for radial variations of wood properties

Property	Model	Fixed-effect parameters					Random-effect parameters
Property	Model	Parameter	Estimates	SE	t-value	p-value	Parameter	SD	Variance component	Variance component ratio (%)
Wood fiber length	c-1	c₀	0.2991	0.0326	9.162	< 0.001	Tree_0j	0.0220	0.0005	2.6
Wood fiber length		c₁	0.9300	0.0543	17.117	< 0.001	e_ij	0.1354	0.0183	97.4
Vessel element length	c-1	c₀	0.0545	0.0125	4.370	< 0.001	Tree_0j	0.0273	0.0007	38.5
Vessel element length		c₁	0.6226	0.0143	43.576	< 0.001	e_ij	0.0345	0.0012	61.5
Vessel frequency	c-2	c₀	− 41.55	3.73	− 11.143	< 0.001	Tree_1j	9.66	93.25	27.6
Vessel frequency		c₁	167.70	7.14	23.496	< 0.001	e_ij	15.63	244.28	72.4
Vessel diameter	c-2	c₀	15.469	0.987	15.676	< 0.001	Tree_1j	2.561	6.561	27.7
Vessel diameter		c₁	50.300	1.889	26.622	< 0.001	e_ij	4.135	17.100	72.3
Wood fiber diameter	c-2	c₀	0.767	0.275	2.786	0.007	Tree_1j	3.076	9.461	88.0
Wood fiber diameter		c₁	26.807	1.127	23.785	< 0.001	e_ij	1.135	1.287	12.0
Wood fiber wall thickness	c-2	c₀	0.8169	0.0675	12.094	< 0.001	Tree_1j	0.875	0.765	90.8
Wood fiber wall thickness		c₁	1.2988	0.3133	4.145	< 0.001	e_ij	0.278	0.077	9.2
Air-dry density	c-2	c₀	0.0479	0.0075	6.345	< 0.001	Tree_1j	0.0395	0.0016	71.3
Air-dry density		c₁	0.3562	0.0176	20.258	< 0.001	e_ij	0.0250	0.0006	28.7
MOE	c-1	c₀	0.9634	0.2047	4.707	< 0.001	Tree_0j	0.2247	0.0505	11.2
MOE		c₁	4.7813	0.2927	16.333	< 0.001	e_ij	0.6344	0.4025	88.9
MOR	c-2	c₀	9.038	1.718	5.262	< 0.001	Tree_1j	4.680	21.907	39.8
MOR		c₁	46.800	3.087	15.161	< 0.001	e_ij	5.756	33.135	60.2
Compressive strength	c-2	c₀	2.140	0.810	2.642	0.011	Tree_1j	1.659	2.753	26.9
Compressive strength		c₁	27.247	1.375	19.819	< 0.001	e_ij	2.735	7.481	73.1

MOE, modulus of elasticity; MOR, modulus of rupture; SE, standard error; SD, standard deviation. Fixed- and random-effects parameters were estimated by the selected model (Table 3)