The Crown
The crown of a tree is located above the trunk and comprises all the branches and leaves present on the tree. The leaves perform photosynthesis, during which they absorb sunlight and interact with chlorophyll to produce the essential sugars needed to nourish the tree. Additionally, a byproduct of this process is oxygen. Leaves come in various shapes, including broad and flat varieties, as well as needle-like forms; however, they all share the common ability to conduct photosynthesis.
As trees are classified as vascular plants, the leaves are interconnected with other parts of the plant through a continuous vascular system. This system facilitates the exchange of nutrients, water, and the final products of photosynthesis, such as oxygen and carbohydrates, among the different components of the plant.
The Trunk
The trunk of a tree consists of several layers, which include:
- Outer Bark: This layer protects the tree from fires and pests, while insulating it from extreme heat and cold.
- Phloem: This layer comprises a network of cells that acts as a pipeline for transporting sugars from the leaves to other parts of the tree. When the phloem cells die, they contribute to the outer bark.
- Cambium: The cambium is the growing portion of the trunk, responsible for producing new phloem and xylem each year. This layer grows slowly during the winter, leading to the formation of annual growth rings, which help determine the age of the tree. The oldest part of these rings is found at the inner section of the tree.
- Xylem: This pipeline transports water and nutrients from the roots to the leaves. The formation of new xylem layers causes the internal layers to die, transforming them into the dense heartwood found in the trunk.
- Heartwood: The heartwood is dead wood situated at the center of the tree that provides structural strength.
The Roots
The primary functions of the roots include absorbing water and nutrients from the soil while anchoring the tree in the ground. They also serve to store sugars. All trees possess lateral roots that extend horizontally into smaller roots. Some trees feature a taproot system that can extend downwards up to 15 feet. Each of these roots is covered with thousands of root hairs that facilitate the absorption of water and minerals from the soil. Most root structures are located in the upper soil layers, typically between 12 to 18 inches deep, which is the area with the highest concentration of oxygen.
Roots can grow downwards, sideways, or along the trunk of the tree. The direction of root growth is determined by a transformative system that converts physical signals into physiological responses, regulating the anatomical and morphological development of the roots.