Sap flow rates and sapwood density are critical factors in within- and between-tree variation in CO2 efflux from stems of mature Dacrydium cupressinum trees
Article first published online: 16 JUN 2005
Volume 167, Issue 3, pages 815–828, September 2005
How to Cite
Bowman, W. P., Barbour, M. M., Turnbull, M. H., Tissue, D. T., Whitehead, D. and Griffin, K. L. (2005), Sap flow rates and sapwood density are critical factors in within- and between-tree variation in CO2 efflux from stems of mature Dacrydium cupressinum trees. New Phytologist, 167: 815–828. doi: 10.1111/j.1469-8137.2005.01478.x
- Issue published online: 16 JUN 2005
- Article first published online: 16 JUN 2005
- Received: 23 January 2005 Accepted: 17 April 2005
- CO2 efflux;
- Dacrydium cupressinum;
- sap flux density;
- sapwood density;
- stem respiration;
- xylem transport
- • Measurements of CO2 efflux from stems and branches, sap velocity, and respiratory activity of excised wood cores were conducted in Dacrydium cupressinum trees that differed in diameter, age, and canopy emergence. The objective of this study was to determine if consistent linkages exist among respiratory production of CO2 within stems, xylem transport of CO2, and the rate of CO2 diffusing from stem surfaces.
- • Stem CO2 efflux was depressed during periods of sap flow compared with the efflux rate expected for a given stem temperature and was positively correlated with sapwood density. By contrast, no significant relationships were observed between CO2 efflux and the respiratory activity of wood tissues.
- • Between 86 and 91% of woody tissue respiration diffused to the atmosphere over a 24-h period. However, at certain times of the day, xylem transport and internal storage of CO2 may account for up to 13–38% and 12–18%, respectively, of woody tissue respiration.
- • These results demonstrate that differences in sap flow rates and xylem anatomy are critically important for explaining within- and between-tree variation in CO2 efflux from stems.