Results of the fit of exponential functions on the excess of 13C in leaves and the cumulative excess of 13C in soil CO2 efflux related to time after labeling.

Shown are the amount of labeled carbon that was recovered in a given compartment as parameters a and c, being expressed as the relative size of a fast and a slow pool, the mean residence time (MRT) and the half life of both pools, and the coefficient of determination (R2). Please note that the size of the pools refer to the percentage of the overall assimilated 13C.†No separation between fast and slow pool could be made.