No treeline shift despite climate change over the last 70 years

The recent rise in temperature and shifting precipitation regimes threaten ecosystems around the globe to different degrees. Treelines are expected to respond to climate warming by shifting to higher elevations, but it is unclear whether they can track temperature changes. Here, we integrated high-resolution aerial imagery with local climatic and topographic characteristics to study the treeline dynamic from 1945 to 2015 on the semi-arid Mediterranean island of Crete, Greece. During the study period, the mean annual temperature at the treeline increased by 0.81 ​°C, while the average precipitation decreased by 170 ​mm. The treeline is characterized by a diffuse form, with trees growing on steep limestone slopes (>50°) and shallow soils. Moreover, the treeline elevation decreases with increasing distance from the coast and with aspect (south ​> ​north). Yet, we found no shift in the treeline over the past 70 years, despite an increase in temperature in all four study sites. However, the treeline elevation correlated strongly with topographic exposure to wind (R2 ​= ​0.74, p ​