Phenotypic plasticity of natural Populus trichocarpa populations in response to temporally environmental change in a common garden

Table 2 Variance partitioning of phenology and biomass traits using REML-linear mixed models for the comparison of trait responses across 29 Populations over two years and Year × Population interactions

		Bud set			Canopy duration			Growth period			Leaf drop			Post-bud set period			Active growth rate			Height: diameter
	N DF	D DF	F/ χ²	P	D DF	F/ χ²	P	D DF	F/ χ²	P	D DF	F/ χ²	P	D DF	F/ χ²	P	D DF	F/ χ²	P	D DF	F/ χ²	P
Popltn	28	582	44.02	< 10⁻⁴	509	21.44	< 10⁻⁴	547	36.11	< 10^− 4	619	42.20	< 10^− 4	497	23.464	< 10^− 4	573	17.53	< 10^− 4	609	13.03	< 10⁻⁴
Year	1	424	297.48	< 10⁻⁴	458	441.68	< 10⁻⁴	436	556.53	< 10⁻⁴	439	263.22	< 10⁻⁴	410	93.455	< 10⁻⁴	444	123.08	< 10⁻⁴	456	1.40	1
Popltn × Year	28	424	6.08	< 10⁻⁴	459	2.55	0.004	437	5.48	< 10⁻⁴	439	7.26	< 10⁻⁴	411	6.913	< 10⁻⁴	445	3.18	< 10⁻⁴	456	2.44	0.001
Genetics	1	NA	54.79	< 10⁻⁴	NA	6.31	0.12	NA	27.22	< 10⁻⁴	NA	92.109	< 10⁻⁴	NA	11.424	0.008	NA	45.39	< 10⁻⁴	NA	80.167	< 10⁻⁴
Model fit statistics	R²	0.878			0.735			0.846			0.894			0.714			0.763			0.718
	AIC	6393.95			6381.67			6751.05			5372.29			6050.42			−42.16			5953.03
	REML	6273.95			6261.67			6631.05			5252.29			5930.42			− 162.16			5833.03

We report on F-values for fixed effects and on χ²-values for random effects (i.e., ‘Genetics’). Significance of random effects was assessed using likelihood ratio tests. Significant P-values after the sequential Bonferroni correction (α = 0.05) are shown in bold. Denominator degrees of freedom (D DF) are calculated using the Satterthwaite’s approximation as implemented in the R package lmerTest. Popltn: Population. Variance-partitioning for ecophysiology traits reported in Additional file 1: Table S3

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