One summer, two men came to the countryside for their holiday.
While walking through an orchard, they noticed all the trees were bending under the weight of abundant apples, except for one tree which bore no fruit at all.
A young country boy was sitting nearby. They called to him, "Come here, boy. Here's six pence for you. Do you know why there are no apples on that tree?"
"Of course I do, sir," the boy answered. "Because it is an oak tree."