The needles make sugar for the tree by combining water, which the tree gets from the roots, with carbon dioxide from the air. This process is known as photosynthesis and is made possible through the action of chlorophyll, present in the needles, in combination with the energy of the sun. Oxygen is given off as a by-product.
All of the trunk’s growth takes place in a thin layer of living cells that surround the inside core of “dead” wood. This layer creates new wood on one side and new bark on the other. It moves outward, pushing the bark before it and leaving wood behind.
The water collecting mechanism for the tree is in the tiny, nearly invisible hairs behind a protective cap on the root tip. There are millions of these hairs in each tip that absorb moisture and minerals from between individual grains of soil. The roots of the tree are fed by the sugars produced in the leaves during photosynthesis.
Instead of growing downward, most of the tree’s roots grow outward forming a crisscross net that anchors the tree to the ground.
The energy of the tree lies dormant over the winter. In the spring, as the plant grows, the energy flows upward from the roots, making needles. After the needles are established, their energy flows downward to the roots whence it is their turn to grow. When the cold of winter comes, the tree, once again rests.