Non-radiative heat dissipation across scales in a water stressed pine forest: from the leaf to the planetary boundary layer

Warming, drying, and intensified water stress is expected in many ecosystems over the next century. In dry environments, evaporative cooling becomes increasingly limited and must be replaced with alternative means of heat dissipation if canopy and leaf temperature are to be maintained within the physiological range and mortality avoided. We have shown that in dry environments when latent heat flux is minimal, net radiation is high, and thermal radiation emission is suppressed, pine forest canopies can efficiently cool through a massive sensible heat flux, facilitated by the low aerodynamic resistance of the open canopy (a so-called ‘Convector Effect’). Using novel methodology, we also show that this phenomenon may originate at the leaf-scale, associated with needle properties, changes in heat transport characteristics across the canopy profile, and propagating across scales can ultimately influence the boundary layer, the local atmospheric dynamics, and potentially regional climate.