  We present here experimental results on the effect of a forest of cylinder
obstacles (nails) on the stability of a granular layer over a rough incline, in
a so-called "fakir plane" configuration. The nail forest is found to increase
the stability of the layer, the more for the densest array, and such an effect
is recovered by a simple model taking into account the additional friction
force exerted by the pillar forest onto the granular layer.
