Fig. 1

According to the weighting of the NMR decay, different parameters can be measured such as proton density, longitudinal (T₁) and transverse (T₂) relaxation times, diffusion (ADC) and flux. Subset (a) represents proton density and T₂ maps acquired on a Fagus sylvatica stem (Adapted from [10] with permission from Wiley). Subset (b) represents an ADC map acquired on a pear tree (Adapted from [11] with permission from AIP Publishing). Subset (c) represents an example of flux measurements. It corresponds to the average linear velocity map of a poplar tree stem (Adapted from [12] with permission from Blackwell Publishing Ltd). The red scale corresponds to the velocity measured in the phloem, while the blue scale corresponds to the velocity measured in the xylem