How Does a Tree Survive?

Have you ever considered how a tree, which can live hundreds or even thousands of years, manages to survive so long on not much more than sun, air and water?

A tree operates somewhat like an efficient pump -- it moves gallons of moisture from the soil to its leaves. First we must know that water molecules tend to attract each other. So one molecule will evaporate from a leaf, and another molecule will move upwards through the tree trunk to replace it. The natural force of a tree trunk's ability to move water is strong enough to send a column of water from the ground to the top of redwoods more than three hundred feet tall!

When a tree begins, it contains very slender, fine sapwood tubes in the trunk which carry the tree's water supply. As a tree ages, these tiny tubes will fill with resin and other by-products and becomes heartwood. Heartwood becomes the supportive core of a tree, although it cells are technically dead. The heartwood is protected by layers which protect it from rotting. New water-carrying tubes form in a growing layer called cambium. This occurs in rainy season in the area, in most locations, during spring.

As the tree continues growing, cells will begin to form in an outer layer called the phloem. The outer layer carries sap through the tree and tips of branches, as well as to the roots. The sap is full of nutrients for every living part of the tree. Food that isn't needed is then stored in the roots for winter, or any time when the tree is dormant or in drought conditions. Bark on the very outer layer is protective insulation for the tree, shielding it from insect and weather damage.

Roots are a fascinating part of a tree. They instinctively know to grow in the direction of water, even in dry rocky soil. Roots have the ability to survive at a lower temperature than any other part of a tree. The three types of roots are taproots, lateral roots, and feeder roots.

Taproots grow straight down into the earth, to act as a sort of anchor for the tree. Trees in rain forests do not have taproots as they need a stronger buttress at the base of the tree to support their great height. Thus rainforest trees feature a stronger thick structure at the ground.

Lateral roots are close to the ground's surface, extending outward from the tree trunk and taproot. They take in oxygen, and also help support the tree.

The small feeder roots, located at the ends of the lateral roots, feature branches which take in water and mineral nutrients for the tree.

Tree leaves are both lovely and fascinating. When the sunlight reaches a leaf's tightly packed cells, the chlorophyll in them turns carbon dioxide and moisture into sugar and oxygen. This is the process called photosynthesis. The sugar is the vital lifeblood of the tree, providing it with energy to grow. In the leaf's spongy layer, necessary gases diffuse throughout air spaces. Under the leaf, there are small pores called stomata which open and shut, allowing the gases to circulate between the leaf and the air outside. When the leaf's veins carry the water and sugar, it causes the leaf to stiffen, similarly to how a hose stiffens when filled with water.

The next time you appreciate the beauty of a tree, take a moment to think about the various activities going on inside it, and the amazing functions it performs.