Variations in gas components and total pressure in stem and root disc wood of conifer species

Resumo

The content of CO₂ and H₂O in vacuum-extracted tree-ring wood of stem and root discs of certain conifer species was measured. Annual distributions of these gas components were found to exhibit cyclic behavior. Moreover, distinct cyclicity was also revealed in interannual variations of the total pressure of the vacuum-extracted tree-ring gas samples. It may be safely assumed that diffusion of stem CO₂ into the atmosphere will show the same periodic variability. Two hypotheses about the origin of the cyclicity in the treering CO₂ distributions are examined.