Recent growth changes in Western European forests are driven by climate warming and structured across tree species climatic habitats

Table 10 Relationships between recent climatic trends (period 1982–2007) in annual averages of minimum (Tn), mean (Tm) and maximum (Tx) temperature, total precipitation (P) and associated climatic averages over the same period

Climatic variable	Climatic trend variation (°C/°C or mm/mm)	Significance and intensity of variation (p and R ²)
Tn (°C)	–0.18	0.01, 0.67
Tm (°C)	–0.09	0.03, 0.57
Tx (°C)	+0.006	NS, 0.01
P (mm)	+0.12	0.02, 0.63

Each climatic trend ΔX (Table 1) was regressed linearly (OLS regression) against climatic average X (1982–2007) as ΔX = a + bX. Figures provided in the table correspond to the slope of variation of climatic trend with climatic average (°C/°C or mm/mm). The pm value of nullity test of b and the regression R ² are also provided. The relationship between climatic trend and average climate over 1982–2007 was negative and significant for minimum and mean annual temperature (which corresponds to a more intense climatic warming over colder samples), and positive and significant for precipitation

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