Stomatal conductance of two tropical trees during the wet season in Nigeria.
Measurements of stomatal conductance were made on teak (Tectona grandis) and Gmelina arborea on 5 days during the wet season in Nigeria. Both species displayed very high conductances but, when compared in the same conditions, values for Gmelina were less than those for teak. Stomatal conductance was mainly determined by the quantum flux, although the saturation deficit of the air also exerted an effect. Transpiration rates were calculated from the stomatal conductances, using the Penman-Monteith equation. The rates were high, and imply that almost all the net radiation was used to evaporate water. Sensitivity analysis showed that transpiration rate for much of the day is insensitive to changes in the stomatal conductance, the aerodynamic conductance or the leaf area index. It is however closely coupled to net radiation.