 Ongoing hillslope processes can change the topology of the hillslope surface, which in turn can change the rates of those processes.Hillslopes that steepen up to certain critical thresholds are capable of shedding extremely large volumes of material very quickly, making hillslope processes an extremely important element of landscapes in tectonically active areas.On the Earth, biological processes such as burrowing or tree throw may play important roles in setting the rates of some hillslope processes.