Table 1 The land area where tree growth responded significantly (P < 0.1) to different climate parameters has changed between 1930–1960 and 1960–1990 CE.

The most pronounced changes occurred for areas that respond positively to temperature (Tint > 0) and negatively to atmospheric water demand (VPDint < 0). By contrast, the responses to precipitation (Pint > 0) and the standardized precipitation evapotranspiration index (SPEIint > 0) remained relatively stable. Δ is the change between 1930–1960 and 1960–1990 CE. The total land area that falls within the climate envelope of the tree-ring network is 80.4 Mio km2.

TimeAreaTint > 0Pint > 0VPDint < 0SPEIint > 0
1930–1960Mio km220.8 ± 3.777.5 ± 3.366.0 ± 1.678.0 ± 1.3
%25.9 ± 4.696.4 ± 4.182.0 ± 2.097.0 ± 1.6
1960–1990Mio km212.1 ± 3.177.4 ± 0.874.7 ± 1.777.4 ± 0.8
%15.1 ± 3.996.2 ± 1.092.8 ± 2.196.2 ± 1.0
ΔMio km2−8.7 ± 0.6−0.1 ± 2.68.7 ± 0.1−0.6 ± 0.5
%−10.8 ± 0.7−0.2 ± 3.210.8 ± 0.2−0.8 ± 0.6