Rapid Response of Tree Cellulose Radiocarbon Content to Changes in Atmospheric sup 14 CO sub 2 Concentration

摘要

A detailed radial profile for the sup 14 C concentration in tree cellulose, covering growth rings for the years 1962-1964, was obtained for a Sitka spruce of the US Pacific Coast using accelerator mass spectrometry. The tree cellulose sup 14 C closely follows atmospheric sup 14 CO sub 2 concentrations, responding to changes with a delay of not more than a few weeks. The delay in response is mostly due to the addition of between 13 and 28% of biospheric CO sub 2 to the canopy-air CO sub 2 used by the tree for stem cellulose. Delayed incorporation and the use of stored photosynthate of the previous fall appear less important. 63 refs., 4 figs., 3 tabs. (ERA citation 13:022812)