Aclassical example for the mismatch between climate station data and the temperatures
experienced by plants are low-stature alpine biota, which ‘collect’ substantial
solar heat, in contrast to upright trees, which are constrained by their architecture,
which thus explains their high elevation limit (the treeline). By their stature, trees
track air temperature and prevent solar heating of their soils by shading the ground,
once the canopy has closed. It then does not come as a surprise that treeless alpine
vegetation several hundred meters above treeline experiences a warmer season than
treeline trees (K¨orner & Paulsen, 2004) and the alpine vegetation has a temperature
of 22◦C optimum for photosynthesis, similar to lowland grassland plants (K¨orner,
2003a). Depending on growth form, temperatures in prostrate vegetation may be 3–20 K above air temperature during sunshine periods