Decreasing trend and fluctuations in the mean ring density of Norway spruce through the twentieth century

Free Access

Table II

Statistics of mixed-effects linear models. Figures in brackets are standard deviations of parameters.

	m	a	b	c	d	σ_site(μ_j)	σ_site(β_j)			AIC

M1	–5.24 (5.9)	–1.09 (0.12)	23.21^** (1.94)	464.5^** (28.7)	–0.35^** (0.06)	17.94	4.36	30.45	228.2	50 248
M2	10.19^◦ (9.68)	–0.93^** (0.14)	23.18^** (1.94)	459.1^** (28.8)	–0.32^** (0.06)	19.98	4.33	29.2	227.8	50 246
M3	14.95^◦ (11.34)	–0.55^** (0.15)	18.53^** (2.02)	415^** (29.9)	–0.35^** (0.06)	19.4	4.4	30.42	240.3	50 042
M4	13.88^◦ (13.02)	–0.55^** (0.14)	18.66^** (1.91)	424^** (28.4)	–0.28^** (0.05)	19.7	4.35	30.21	226.3	49 116

^◦

p-value > 0.05;

^**

p-value < 0.001. M1: model without computation of the date. M2: model with an integration of a linear form of the date. M3: model with an integration of a decadal scale form of the date. M4: model with an integration of a factorial form of the date.