The paper attempts to establish the hillslope stability response to vegetation clearing in the Moresby Ranges, Western Australia. Since the turn of the century the area has been extensively cleared of native vegetation. At present, mass failure of hillslopes, through a variety of failure modes, is widespread in the area. Stability calculations show that the "immediate" cause of failure are debris mantle saturation and the development of high positive pore water pressures. But by considering the root strength that the native vegetation imparted to the debris mantle, it is clear that the "ultimate" cause of hillslope failure is the clearing of native vegetation.