An old man applies for a job as a woodcutter, but the boss doesn’t think he’s fit enough.
He tells the boss he is able to cut down any tree in a single swing.

To prove this, he goes outside, hits a five-foot tree with his ax, and it falls over.
The boss is impressed.

The old man then repeats this with a ten-foot tree.
Then a thirty-foot tree. Finally, he takes his ax up to an 80-foot redwood, swings, and the giant tree comes tumbling down.

The boss is amazed and asks the man how he learned to do that.
The man says “I practiced in the Sahara forest.”
“Don’t you mean the Sahara desert?” The boss asks.
“Well yes,” says the old man, “that’s what they call it now.”