The world's treelines parallel the snowline
Globally, the treeline parallels the snowline, a boundary purely determined by physics above which all precipitation falls as snow.
1 - The latitudinal position of treeline and
snowline (Körner 2003).
True climatic treelines are found at similar growing season mean temperatures of between 5 °C and 7 °C around the globe, suggesting a common thermal limit of tree growth (see Fig. 3).
2 - Temperatures at climatic high elevation treelines for
various latitudes (sites for which the seasonal course of temperature was
available).
