A PolInsar analysis has been conducted on the Nezer forest (Southern France) at P band on high resolution SAR data acquired with the ONERA RAMSES system in January 2004. The Nezer forest is constituted by parcels of pine trees, which are characterized by different tree ages. It is an artificial forest and is managed by the French agronomic research center (INRA), providing an accurate and extensive ground truth. Allometric relations linking height to age and height to biomass have been established for the Nezer forest case. Several tracks with the same route were flown in order to allow multi-pass interferometry processing. P-Band electromagnetic waves are known to penetrate deeper in the vegetation, resulting in a significant contribution of the ground or ground-trunk return to the total forest backscatter for all the polarisations. This is certainly hampering the usual RVoG algorithm for which the HV return is often assumed to be dominated by the volume contribution. The specificity of P Band PolInSAR data over vegetation is detailed and compared to the L-Band behaviour over the same site and forest stands. An inversion technique based on the well-known RVoG algorithm but specifically adapted to P-Band is presented and its performances provided. Furthermore, the potential of a dual-pol polInSAR dataset for vegetation characterisation is discussed on this dataset.