Trees use water and carbondioxide and sun. From this, they make sugars. In order to make any more complex molecules that contain more than hydrogen, Carbon or Oxygen the plant needs access to fertilizer. The elements in there are stored so plants can go a long time between fertilizer. But it does need it. And for optimal growth, it needs vairly continuous acces to the fertilizer.
Why fertilizer you use is not all that relevant as long as you also provide trace elements, which are components that are needed in very small amounts.