After a severe storm, the farmer noticed that a large tree had fallen near his field. However, the farmer and no others were present when the tree toppled over. Did the toppling of the tree make a sound?

Yes and No! Yes, it makes a sound, that being a disturbance in the fluidic medium, air. When the tree falls it causes a disturbance in the air pressure field near his field and that pressure field emanates away from the fallen tree.