The primary use of splitters is to cut up firewood ready to be burned, but they can also be used to make fallen trees easy to dispose of. You have a choice of vertical or horizontal models (which describes the way that the splitting wedge falls), but some models come with both capabilities.
When looking at log splitters for sale, it is important to choose one that is appropriate for the type and size of wood that you are hoping to split. You should also consider whether a vertical or a horizontal model will best suit your needs (or you could be safe and get one that does both!).