1896  Think of boards drawn from the mill by oxen on two crotches, then put into cribs in the river. . . .
1898  (1963)  "Crotch? Why that was a thing my old man made to haul logs on. It quirled up at the nose like a sled and sprauled out so-fashion. You see one end of the logs laid on the crotch an' tother end drug behind."
1912  A rough tongueless sled, made out of the fork of a tree and called a "crutch," was used for drawing the logs on.