Since the terrain slope cannot be neglected for forest height inversion with polarimetric synthetic aperture radar interferometry (PolInSAR), a sloped random volume over ground (S‐RVoG) model is proposed to correct the terrain distortion for forest parameters estimation. A significant model complexity reduction is achieved by aligning the reference frame along the local terrain slope and changing the corresponding radar geometrical configuration. The proposed S‐RVoG model inversion promises to provide much more accurate estimation of forest parameters and is validated with L‐band PolInSAR data produced by PolSARpro software developed by the European Space Agency (ESA).