Our planet supports thousands of tree species through their entire lifecycle. All trees, regardless of species, grow in the same manner. Overall, each tree is structured with the same basic components. The three main parts of the tree are the roots, the trunk, and the crown. All three portions of the tree develop as the tree ages. The roots grow thicker and spread deeper into the soil. On the other hand, the trunk grows taller and thicker. Additionally, the trunk gains all the layers of the bark. Finally, the crown grows to the natural shape of the tree gaining leaves, branches, and buds.
Every tree begins as a seed. The seed size varies based on the species of the tree. Naturally, seeds are spread by animals, birds, wind, and storms. Many trees produce male and female portions on one tree. However, other tree species must be near the matching pair to reproduce successfully. In fact, apple trees need to be planted around other apple trees to produce apples.
Trees take from the environment to take root and grow. Throughout their life cycle, trees continue to take nutrients from the air and soil. However, the tree also gives back to the environment through photosynthesis. Finally, the tree returns what it has taken from the environment with its death and decomposition.
Altogether, the growth process for a tree is:
- Seed pollination and dispersal
- Setting roots
- Immature growth
Seed Pollination and Dispersal
Every tree starts from a single seed. Trees produce their own seeds and use nature to disperse the seeds. One of the most common ways for seeds to spread is by animals. Animals pick up fallen seeds and carry them away. Oftentimes, animals and birds will consume the seeds. After digestion is complete, the seeds will be dispersed on the ground through feces. Animals and birds can also disperse seeds on their fur and feathers.
Another method is from an explosion. The sandbox tree grows seeds in large pods that fall to the ground and explode. The explosion spreads the seeds in a wide radius. The speed at which the seeds explode is incredibly dangerous. In fact, falling seed pods can be deadly to an unsuspecting bystander.
Natural elements like wind and water are excellent methods of seed dispersal. However, the seeds must be water resistant to withstand water dispersal.
Overall, the shape of the seed will determine the best dispersal method. Many seeds fall to the ground and never move far from the parent trunk. However, many of those seeds do not germinate.
After a seed is dispersed, environmental conditions must trigger early growth. There are many conditions that must be met including water, temperature, and germination. When all conditions are met for the seed, the seed will split open and the first root will appear.
The first root of the tree is known as the tap root. It will travel through the soil to secure the position of the seedling. In this state, the seedling is prone to poor weather conditions, flooding, drought, and animal or human interference. Over time, the taproot thickens and stretches deeper into the soil.
As the tap root grounds itself in the soil, the stem of the trunk grows towards the sky. The stem seeks oxygen, carbon dioxide, and sunlight to perform photosynthesis. Additionally, the tap root will absorb nutrients for the tree to use.
Smaller roots will begin to spread off the tap root to create a more secure base and absorb more nutrients.
Over the course of a growing season, the seedling will continue to grow in all directions. The tree is considered a seedling until the stem of the trunk is over one inch in diameter. At this point, the tree becomes a sapling. However, it is still susceptible to weather conditions.
After the tree becomes a sapling, it will follow a traditional growth cycle. The sapling will grow in the spring, summer, and fall. In the winter, the sapling will stand dormant.
Trees will grow for many years until they reach maturation. Altogether, we consider a tree a sapling until the trunk diameter is 5 inches. Saplings typically have flexible trunks and smooth bark. Additionally, saplings do not produce fruits or flowers.
Overall, trees can grow for ten to twenty years before reaching full maturity. In the early years, the tree is susceptible to damage by wind, storm, and frost. Strong and deep roots will protect the tree as much as possible. Larger mammals can also damage young trees by consuming twigs and leaves. Without the leaves, photosynthesis is slowed.
It may surprise many how large a tree can be without reaching maturity. This is especially true for trees that grow to enormous sizes. In the end, trees with long lifespans reach maturity later in life. There are some species that grow quickly, as fast as 4 feet per year. In this case, the tree will reach maturity in just a few years. However, this quick growth rate and maturity come at the cost of a short life.
A tree reaches maturity when it can produce flowers or fruits. For quick-growing trees, maturity is reached in a few years. However, most trees will not reach maturity for at least 20 years.
Altogether, most of a tree’s life is spent in a mature state. It will continue the seasonal cycle of new life, flowering, and dormancy every year. As winter approaches, leaves will fall from deciduous trees to the ground to fertilize the soil in the spring.
Mature trees are the most productive for seeds and fruits. Overall, mature trees can still be susceptible to severe weather conditions but will stand up to most storms. Mature trees can be dangerous to man made dwellings in storms because of their size and weight.
Before a tree truly dies, it reaches a state of old age. At this stage, it severely slows fruit production. Trees in this stage are referred to as ancient trees. Ultimately, the term ancient is not completely tied to thousands of years. In order to characterize a tree as ancient, you must look for key characteristics. These characteristics include a wide trunk, hollow trunk, small canopy, and a lack of flower or fruit production.
There are many factors that can result in the death of a tree. Natural disasters and severe weather like floods, forest fires, windstorms, and human interference leading to erosion can all lead to the death of trees. Additionally, diseases or infestations can shorten the life of a tree.
The final stage of the tree life cycle is death. Trees do not need to fall to be classified as dead. There are many standing trees that are dead.
To classify a tree as dead, it cannot grow leaves or needles. It will no longer perform photosynthesis.
Even in death, the tree can support the organisms around it. Birds, mammals, bacteria, and fungi all thrive around the dead tree. Additionally, as the tree decomposes, it gives nutrients back to the ear to support new plant life.