STEM AND BRANCH RESPIRATION OF TREES IN ELEVATED CO2 ENVIRONMENTS
The primary objective of this research was to monitor the effects of increased [CO2] concentrations on tree respiration. The studies were conducted on the Free Air Carbon Dioxide Enrichment (FACE) site. A Licor (portable photosynthesis system) was used to monitor the respiration in the tree bole and branches. Increases in CO2 were recorded four times every twenty seconds at each reading. Other factors, such as air temperature, stem temperature and time of day were also monitored. Readings on several different occasions showed the trees in rings one and two (high CO2) were respiring at a higher rate than those in four and five (controlled), and there were no significant differences between the ambient and controlled rings. It also showed respiration rates increased as living tissue increased. This study is only a glimpse of the big picture. It must be considered with similar studies on other tree physiological processes, such as photosynthesis.
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