graze at levels where mature trees are not debarked and there is limited bare ground around the base of trees (<10% of trees have bare ground around their base)
pori ar lefelau lle nad yw coed aeddfed yn cael eu rhisglo a lle nad oes llawer o dir moel o amgylch bôn coed (mae gan <10% o goed dir moel o amgylch y bôn)