Variations and trends in CO 2 and H 2 O content in coniferous tree-rings

The experimental values of the variation in the CO2 and H2O content in tree-rings of some conifers from regions with different climate conditions have been obtained. These data are compared with tree-ring widths; some conclusions are made about the climatic response in the annual CO2 and H2O distributions. The hypothesis is proposed that the long-term cyclicity found in the annual CO2 distribution over tree rings is a response of trees to environmental changes.