Skip to Main Content
Estimating maximum mean canopy stomatal conductance for use in modelsAuthor(s): Brent E. Ewers; Ram Oren; Kurt H. Johnsen; J.J Landsberg
Source: Can. J. For. Res. 31: 198207 (2001)
Publication Series: Miscellaneous Publication
PDF: View PDF (285 KB)
DescriptionFertilized (F) and irrigated and fertilized (IF) stands of Pinus taeda L. produced twice the leaf area index of irrigated (I) and control (C) stands. Based on sap flux-scaled mean stomatal conductance (GS), we found that stomatal conductance in F was half that in other treatments. During the growing season, GS was related to vapor pressure deficit (D) and soil moisture. During the cooler season, soil moisture was high and light accompanied D in controlling GS. Under all conditions and treatments, the rate of decrease in GS with D was proportional to GS at low D (= 1 kPa). We evaluated whether GS can be used as an input to growth models and used a simple growth model (3-PG), which also predicts stand transpiration (EC), to compare with direct EC measurements in the four stands. Model predictions of monthly EC based on Penman Montieth equation parameterized with maximum GS (GSmax) estimated under highest "native" soil moisture (0.07 m3·m3) produced long-term values within 10% of measured EC. When the model was parameterized with GSmax estimated under experimentally raised soil moisture, or with porometrically measured conductance, EC values were consistently overpredicted from 12 to 33%. Thus, sap-flux scaled mean canopy stomatal conductance obtained under non limiting light conditions, low D, and highest native soil moisture, is the most appropriate parameter value for certain single-leaf type of models.
- You may send email to email@example.com to request a hard copy of this publication.
- (Please specify exactly which publication you are requesting and your mailing address.)
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
CitationEwers, Brent E.; Oren, Ram; Johnsen, Kurt H.; Landsberg, J.J 2001. Estimating maximum mean canopy stomatal conductance for use in models. Can. J. For. Res. 31: 198207 (2001)
- Carry-Over Effects of Water and Nutrient Supply on Water Use of Pinus Taeda
- Fertilization intensifies drought stress: water use and stomatal conductance of Pinus taeda in a midrotation fertilization and throughfall reduction experiment
- Radiation-use efficiency and gas exchange responses to water and nutrient availability in irrigated and fertilized stands of sweetgum and sycamore
XML: View XML