Seasonal changes in leaf area, stomatal and canopy conductances and transpiration from bracken below a forest canopy.
Abstract
Leaf area index and stomatal conductance of the bracken (Pteridium aquilinum) canopy within a pine forest were combined to give canopy conductances. Transpiration from the bracken was calculated using these conductance values and appropriate environmental variables in the Penman-Monteith Equation. Calculated transpiration agreed well with independent values derived by weighing transplanted bracken. During exceptionally warm dry periods, transpiration from the bracken accounted for more than half of the total forest transpiration. More usually, the contribution from the bracken understorey was between 20 and 25% of the total transpiration. From summary.<new para>ADDITIONAL ABSTRACT:<new para>Leaf area index and stomatal conductance of the bracken (Pteridium aquilinum) canopy within a pine forest were combined to give canopy conductances. Transpiration from the bracken was calculated using these conductance values and appropriate environmental variables in the Penman-Monteith Equation. Calculated transpiration agreed well with independent values derived by weighing transplanted bracken. During exceptionally warm dry periods, transpiration from the bracken accounted for more than half of the total forest transpiration. More usually, the contribution from the bracken understorey was between 20 and 25% of the total transpiration.