There's multiple natural forces that are considered constructive or destructive. Constructive forces can be the volcanic eruptions, deposition, the deformation of the crust, while destructive forces can be the erosion and the weathering. The constructive forces are the the natural forces that manage to build up and create the landforms, while the destructive forces are the ones that manage to destroy the landforms. In general, the constructive forces are building up, thus making the surface more ragged, creating faults, hills, mountains, valleys. On the other hand, the destructive forces have the tendency to flatten the surface of the Earth, and they practically destroy little by little the landforms created by the constructive forces until they level them up.
