hide
Free keywords:
Essential Ecosystem Variables; Earth Observations
Abstract:
Energy and water limitations of tree growth remain insufficiently understood at large spatiotemporal scales, hindering
model representation of interannual or longer-term ecosystemprocesses. By assessing and statistically scaling the climatic
drivers from2710 tree-ring sites, we identified the boreal and temperate land areas where tree growth during 1930–1960
CE responded positively to temperature (20.8 ± 3.7Mio km2; 25.9 ± 4.6%), precipitation (77.5 ± 3.3Mio km2; 96.4 ± 4.1%),
and other parameters. The spatial manifestation of this climate response is determined by latitudinal and altitudinal
temperature gradients, indicating that warming leads to geographic shifts in growth limitations. We observed a significant
(P < 0.001) decrease in temperature response at cold-dry sites between 1930–1960 and 1960–1990 CE, and the
total temperature-limited area shrunk by −8.7 ± 0.6 Mio km2. Simultaneously, trees became more limited by atmosphericwater
demand almost worldwide. These changes occurred under mild warming, andwe expect that continued
climate change will trigger a major redistribution in growth responses to climate.
