What is the original intention of the wife's answer?

The eldest son played a handful of firewood at his age, the second son didn't play any firewood at all, and the third son played a car full of firewood as a joke. "A bunch of jokes" is a small joke. The wife's answer in the joke is that the eldest son hit a handful of firewood because of his age, and the second son didn't hit any firewood at all. The third son hit a load of firewood for his jokes, among which age, knowledge and jokes are the names of her three sons.