The tree is supplied with essential minerals from the soil, which are used as 'bricks' in the food.
Simultaneously oxygen is given free to the atmosphere.
It is the sugar on which the tree feeds . The sugar is transported through stems and branches and transformed to new wood, new roots, new leaves, flowers and fruits. All that the tree needs to grow and generate. An unused amount to keep for storage better be produced too. If this is not possible, the tree will weaken, loose strength and ability to resist pathogens and damages.