Where does a tree's water come from?

60 gallons per hour is a lot of water. But it's estimated that a big tree, such as a 48 foot maple has on average 177,000 leaves, which adds up to a leaf area of 1/6 of an acre. Each leaf has thousands of tiny pores called stomata on the underside which open up on a nice day and lose water. They need to do this to pull water up through the roots into the stem and up to the leaves, in a process called transpiration. All this water must come from ground water, water stored underground.