Laser Photoacoustic Method for Disc Tree-Ring Gas Analysis

A laser photoacoustic gas analysis was used to study the annual CO2 and H2O trends in tree rings and their comparison with the tree ring width of dry discs was made. The measurements show that 1) the CO2 concentration in gas samples vacuum-extracted from annual tree rings correlates with atmospheric CO2 rise in certain cases; approximately 4-year cycles in CO2 distribution were readily fixed; 2) for the Scots pine discs, years with small tree ring width are characterized by high CO2 concentration, while those with large tree ring width are associated with small CO2 concentration. Abrupt changes in atmospheric conditions are assumed to favour increased amplitudes of one of natural cycles of annual CO2.