Environmental regulation of surface conductance for evaporation from vegetation |
| |
Authors: | E.-D. Schulze R. Leuning F. M. Kelliher |
| |
Affiliation: | (1) Lehrstuhl Pflanzenökologie, Universität Bayreuth, 95440 Bayreuth, Germany;(2) CSIRO Centre for Environmental Mechanics, G.P.O. Box 821, 2601 Canberra, ACT, Australia;(3) Manaaki Whenua-Landcare Research, P.O. Box 31-011, Christchurch, New Zealand |
| |
Abstract: | We examine conductances for evaporation from both vegetation and soil in response to environmental variables. Data from a vertically-structured pristine forest of Nothofagus are presented as an example of the effects of biodiversity on the scaling of conductances between tiers of plant organisation. Available data sets of maximum leaf stomatal conductances (glmax) and bulk vegetation surface conductances (Gsmax) are compared. Overall, the ratio Gsmax/glmax is consistently close to 3 for seven major vegetation types of diverse structure. An analytical model accounts for this close relationship, and in particular how Gsmax is conservative against changes in leaf area index because of the compensating decrease in plant canopy transpiration and increase in soil evaporation as leaf area index diminishes. The model is also successfully tested by comparison with canopy conductances of emergent trees measured in the Nothofagus forest. The constraint of vegetation surface conductance and evaporation via environmental regulation by irradiance, air saturation deficit and root zone water supply are discussed. |
| |
Keywords: | Canopy Evaporation Leaf area index Scaling Surface conductance Stomata |
本文献已被 SpringerLink 等数据库收录! |
|