Figure 8
From: Accelerating upward treeline shift in the Altai Mountains under last-century climate change
The variation of mean annual temperature from [ref.29] (left-upper panel) was related to the mean annual growth of the sampled trees and shows a hyperbolic curve (right-upper panel). This can be split in two linear trends at the −4.3 °C threshold (dashed red line) derived from the evidence that before 1978 (dashed black line) temperature never exceeded this value (yellow area). Therefore the estimated temperatures for the missing years in the observations by [ref.29] (lower panels) were derived from the linear regression equations shown in the small inserts of the growth-temperature plot (the dashed black lines represent the linearized trend after the split of the hyperbolic curve), at <−4.3 °C for 1902–1955 and >−4.3 °C for 2010–2017.
