Anyone who observes fruit trees may wonder how or why they behave in specific ways. Some trees grow upright while others have a spreading habit. Some produce many flowers and small immature fruit only to drop most of the fruit later on; others grow more strongly on their sunny side than their shady side. It is common to ascribe such behavior to the tree as a whole and state that trees preferentially "allocate" resources to specific organs. However, this is the wrong approach to understandi...