The verb truncate means to cut off or shorten. You can truncate a board that is too long using a power saw, a chain saw, or perhaps even a karate kick.
The word truncate is from a Latin word, truncare, which means "to maim or to cut off." Although this brings to mind a more grisly image ("truncate a limb in an accident"), you can actually truncate things that are not related to anatomy. You could truncate an essay by omitting a paragraph or two, or you could even truncate your vacation in Belize by heading home early.