Global Mountain Biodiversity Assessment (GMBA)

Treeline definition

Example of treelines in mountains

Climate-based potential treeline

The climatic treeline represents an obvious land cover demarcation. Its relation to temperature makes it an ideal reference line for other bioclimatic zones that are useful for comparing mountains, their habitats, and their biodiversity.

GMBA endorsed the work of Körner and Paulsen (2014) who developed a climate-based model (TREELIM) to predict potential treeline position around the globe. The model identifies three meteorological parameters that constraint the climatic treeline: a threshold value that determines the minimum air temperature for physiological tree activity (definition of the growing season), a minimum growing season duration, and a minimum mean temperature during that season. The model yields best fit with a minimum air temperature of 0.9 °C, a minimum growing season of 94 days, and a minimum mean temperature of 6.4 °C.

Detailed information about the treeline model is available in Körner and Paulsen (2014).