Tree Anatomy 101: A Brief Guide

Trees provide shade, exchange carbon dioxide for oxygen, and keep the local ecosystem healthy. In turn, different environmental conditions affect the tree’s growth and reproduction.

Tree service experts in Fair Oaks, CA, can recognize the well-being of trees in any yard by the tree anatomy. Here are a few notes on your yard’s hardiest plants.

tree anatomy

The Three Main Parts of a Tree

You can generally separate tree anatomy into the roots, trunk, and canopy. Each has special duties to improve the health and growth of the overall plant.


Tree roots anchor the plant to the ground. Its many tissue layers have specialized jobs:

  • Epidermis: the outer layer, protecting the inner root workings
  • Exodermis: later becomes the epidermis, assisting with moisture absorption and gas conversion
  • Cortex: stores energy and transfers nutrients from smaller root hairs to vascular tissues
  • Endodermis: regulates water and nutrient transfers between the soil and vascular tissues
  • Pericycle: supports the tree from the inside of the endodermis and creates new roots
  • Vascular tissue: transports the water and nutrients to the rest of the tree

Some species of tree can even use their roots to reproduce, creating clone trees by forming shoots. Once they reach the surface, they begin growing a new trunk and canopy.


Trunks may vary from species to species, but tree anatomy tends to have the same makeup:

  • Bark: protects the tree as a physical barrier and insulator
    • Inner: transports sap and other nutrients throughout the tree
    • Outer: a layer of dead cells with oxygen-breathing pores
  • Vascular cambium layer: a layer of continually dividing cells that later form into a transport method for the tree’s nutrients
  • Sapwood: an inner section supporting water transport and storage
  • Heartwood: a thick layer of dead cells supporting the tree structure
  • Pith: the centermost point of the tree that assists with central nutrient transport.

We can tell tree ages because of the way these layers restore themselves. In the growing season, the vascular cambium layer expands rapidly and appears light in color. 

After the growing season, the tree spends less energy on these layers, making them thinner and darker. This process forms the rings within the tree trunk.


The canopy, or crown, tends to be the most vibrant and a great general health indicator. Studies and personal accounts have noted that bright green leaves and leaf buds reduce stress and lower blood pressure. Like other tree parts, they have several components, including:

  • Epidermis: an outer layer that helps prevent water loss
  • Mesophyll cells: the middle section of a leaf
    • Palisade: contains the chloroplasts for photosynthesis, converting sunlight into sugars
    • Spongy: allows gas movement within the leaves, absorbing carbon dioxide and releasing oxygen
  • Stoma: small openings in the epidermis for atmospheric gas exchanges
  • Vascular bundle: like veins and arteries, transports the photosynthesized sugars to other tree parts

Count on Us for Your Tree Knowledge

This basic introduction to tree anatomy barely scratches the surface of tree health, wellness, and overall yard protection. From choosing the best shade trees in California to diagnosing sickly branches, you can rely on Ace Tree Service. For informative year-round yard assistance in Sacramento County, call (916) 934-3204 today!