%0 Article
%T A field system for measuring the gas exchange of forest trees.
%A Hari, Pertti
%A Korpilahti, Eeva
%A Pohja, Toivo
%A Räsänen, Pentti K.
%D 1990
%J Silva Fennica
%V 24
%N 1
%R doi:10.14214/sf.a15557
%U https://silvafennica.fi/article/5405
%X <p>A third generation of forest tree gas exchange measuring system design for the use in the field is described. The system is designed to produce data for determining the dependence of the rate of tree photosynthesis, respiration and transpiration on environmental factors. The system consists of eight cuvettes, a tubing system, two infrared gas analysers, an air flow controller, a data logger, and a computer. The measuring cuvette is a clap type, i.e. it is mostly open, only closing during measurement. CO<sub>2</sub> exchange is measured as the change in the cuvette concentration of CO<sub>2</sub>, and, transpiration is measured as the increase in water vapour concentration while the cuvette is closed. The environmental factors measured are&nbsp;temperature, irradiance and air pressure. The system was planned in 1987 and constructed in 1988. It worked reliably in late summer 1988 and the quality of data seems to be satisfactory.&nbsp;</p>
<p>The PDF includes an abstract in Finnish.</p>