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The Basic Anatomy of a Tree

Updated: Jul 8, 2022

With how many species of trees exist throughout the world, they’re all made up of the same anatomical features: leaves, branches, trunks, and intricate rooting systems. If you’re interested in finding out how important each part of a tree is when it comes to keeping it alive, then this is the guide for you!



The leaves are an important part of any tree type, as they carry out the process of photosynthesis and create food for the tree to help keep it healthy. Leaves also release oxygen into the air, providing the means to breathe naturally for all beings. The varying edge types on leaves have their uses as well, helping any water used to reduce wind resistance, for food-building and leftover rain to evaporate so the leaves don’t start to decay.


Branches and Twigs

Growing out of the tree’s trunk, branches and twigs help to support the leaves, flowers, and fruits that the tree may produce. They also work as a transport vessel between the leaves and the trunk. Together with the leaves, the upper section of a tree is known as the crown, working to filter out dust and particles from the atmosphere. Additionally, the crown produces shade for humans and animals, and will protect the ground below from the impact of heavy rainfall.


The Trunk

A tree’s trunk is made up of five distinct layers: the outer bark, inner bark, cambium cell, sapwood and heartwood. The outer bark protects the tree from external threats thanks to its insulating properties, fighting off hot and cold temperatures as well as insects. Furthermore, it keeps out moisture when it rains while still staying moist during dryer seasons.


Also known as the phloem, the inner bark works as a pipeline for food to pass throughout the tree. It has a short lifespan, and when it dies, the inner bark turns into cork and merges with the outer bark for additional protection. As the growing part of the tree, the cambium cell layer creates a new bark and wood thanks to the hormones that pass through the inner bark layer from the leaves. The hormones known as auxins stimulate cell growth and are produced through leaf buds.


Sapwood is another pipeline within the tree, except for it transports water up to the leaves. As new sapwood is created, the ageing wood loses its vitality and turns into the heartwood. At the centre of the tree, the heartwood is the supporting pillar of the entire structure. Even though it’s technically dead, the heartwood doesn’t decay or lose its strength, as long as the outer layers remain intact.


The Root System

The roots of a tree can be found in the top three feet of the soil and can expand much farther outside the crown then you may believe. Growing well beyond the dripline, a tree’s root system can extend two to four times farther than the branches and leaves. The roots absorb water and minerals from the soil; keep the tree secured to the ground and store food for the winter months.


At Arbor Care Tree Service Inc., we offer 24-hour emergency tree service to Oakville, Mississauga, Burlington, Brampton, Etobicoke, Toronto, and the western GTA. Located in Mississauga, Ontario, other tree services include tree pruning, hedge and tree trimming, deep root feeding, and stump and tree removal. Creating a safe and reliable work environment for everyone, give us a call.


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