Estimating Evapotranspiration from Commonly Occurring Urban Plant Species Using Porometry and Canopy Stomatal Conductance

• Main Authors: Syed Hamza Askari, Simon De-Ville, Elizabeth Abigail Hathway, Virginia Stovin
• Format: Article
• Language: English
• Published: MDPI AG 2021-08-01
• Series: Water
• Subjects: evapotranspiration; initial losses; porometry; retention; stomatal conductance; Sustainable Drainage Systems (SuDS)
• Online Access: https://www.mdpi.com/2073-4441/13/16/2262

Evapotranspiration (<i>ET</i>) is a key moisture flux in both the urban stormwater management and the urban energy budgets. While there are established methods for estimating <i>ET</i> for agricultural crops, relatively little is known about <i>ET</i> rates associated with plants in urban Green Infrastructure settings. The aim of this study was to evaluate the feasibility of using porometry to estimate <i>ET</i> rates. Porometry provides an instantaneous measurement of leaf stomatal conductance. There are two challenges when estimating <i>ET</i> from porometry: converting from leaf stomatal conductance to leaf <i>ET</i> and scaling from leaf <i>ET</i> to canopy <i>ET</i>. Novel approaches to both challenges are proposed here. <i>ET</i> was measured from three commonly occurring urban plant species (<i>Sedum spectabile</i>, <i>Bergenia cordifolia</i> and <i>Primula vulgaris</i>) using a direct mass loss method. This data was used to evaluate the estimates made from porometry in a preliminary study (Sheffield, UK). The Porometry data captured expected trends in <i>ET</i>, with clear differences between the plant species and the reproducible decreasing rates of <i>ET</i> in response to reductions in soil moisture content.