Methodologies

Measurement of biosphere-atmosphere exchange of various greenhouse gases requires different techniques. In case of carbon dioxide, the net ecosystem exchange (NEE) is usually measured by the eddy covariance method. In the lack of these measurements in forests, the carbon dioxide uptake can be estimated by detecting changes in sequestrated carbon stocks or by using tree growth (dendrometric) measurements. The soil CO₂, CH₄, and N ₂O efflux/exchange rates can be determined using in situ chamber techniques, or laboratory incubation measurements. Static and dynamic, manual and automatic chamber methods, as well as photo-acoustic, gas chromatography, and infrared detections can be used for this purpose. This chapter gives a general overview of the approaches applied in studies presented in this book for evaluating the greenhouse gas exchange between the biosphere and atmosphere.