A long tool used to measure lengths of up to three feet is called a yardstick. A carpenter carefully measuring lengths of wood before cutting might use a yardstick.
A yardstick is basically a long ruler — three times as long, to be specific — with units marked in inches. Most are made of wood, sometimes hinged so they can be folded, and their size makes them ideal for specific tasks in construction and carpentry. The word yardstick is also used figuratively to mean "standard or benchmark." So you might say that your yardstick for success as a gardener is how many tomatoes you pick over the summer.