simple field method for measuring the gas exchange of small trees

• Published in: Functional ecology Vol. 5; no. 4; pp. 572 - 576
• Main Authors: Mordacq, L, Ghashghaie, J, Saugier, B
• Format: Journal Article
• Language: English
• Published: Oxford British Ecological Association 1991; Blackwell Science
• Subjects: Air flow; Anemometers; Animal, plant and microbial ecology; Biological and medical sciences; Carbon dioxide; Castanea sativa; Ellipsoids; field experimentation; Flow velocity; Fundamental and applied biological sciences. Psychology; gas exchange; growth chambers; Leaf area; Leaves; measurement; Photosynthesis; Plants; trees; Turbines; Gas exchange; Photosynthesis; Small tree; Method study
• ISSN: 0269-8463; 1365-2435
• DOI: 10.2307/2389640

A simple open system is described for in situ measurements of the gas exchange of small trees. A large assimilation chamber, composed of a fixed rigid base and of a frame of aluminium covered with polypropylene film, is supplied with external air by a turbine. As the flow rate is high, no air conditioning is needed. An anemometer, composed of a propeller and of an optical detector, was especially designed to measure large air flows. With this system working on a young chestnut tree bearing 4-5 m2 of leaves, the input-output differential CO2 concentration reaches 20 v.p.m. under high irradiances. In these conditions, the temperature increase does not exceed 4⚬C and the error on tree photosynthesis is less than 15%.