Tag Archives: tree anatomy

Anatomy of a Tree

How knowledgeable are you when it comes to the anatomy of a tree?  Being able to identify parts of a tree is helpful in identifying tree illnesses and safety hazards.  Tweet your tree anatomy questions at us: “@westchestertree”.

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Starting from the Bottom:  The Root System

A healthy root system makes for a healthy tree!  The purpose of the tree’s root system is to anchor the tree, as well as absorb water and minerals from the soil.  There are two kinds of roots, large perennial roots and small, short-lived “feeder” roots.

Did You Know:  Tree roots are typically found in the top three feet of soil.

The Five Parts of a Tree Trunk

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Did you know a tree trunk has five parts?  A tree trunk is comprised of the outer bark, the inner bark, the cambium cell layer, sapwood and heartwood!  

The heartwood is the innermost layer of the tree trunk, and acts as the supporting pillar of the tree.  Though the heartwood is technically dead, it does not decay or lose strength while the outer layers of the tree are intact.  Heartwood is a composite of hollow, needlelike cellulose fibers which are bound together by a chemical-like glue, lignin, making it almost as strong as steel.

The layer which covers the heartwood is the sapwood, which later hardens and turns into heartwood.  Sapwood acts as the trees pipeline for water, helping it move up to the tree’s leaves.

After the sapwood is the cambium cell layer.  The cambium cell layer annually produces new barn and wood in response to auxins, the hormones which are passed down through the tree.  Auxins stimulate growth in cells and are produced by leaf buds at the ends of a tree’s branches.

Next is the Phloem, or the inner bark, which acts as the pipeline for food.  The Phloem only lives for a short time before turning to cork; this cork is part of the tree’s protective outer bark.

Lastly is the outer bark, which protects the tree from the outside world.  This outermost later helps keep out moisture and prevents the tree from losing moisture; the outer bark also insulates against extreme temperatures.

Branches, Twigs and Leaves

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A tree’s branches and twigs spring out of the trunk and are the supportive structure for leaves, flowers and fruit.  Through the process of photosynthesis, leaves make food for the tree and release oxygen into the air.

The 5 Layers of a Tree Trunk

Understanding how to properly care for the trees on your property begins with knowing about the anatomy of a tree.  We’re going to walk you through the 5 layers of a tree trunk!

Anatomy of a Tree Westchester Tree Life

The Outer Bark

The outermost later of a tree trunk is the outer bark.  This insulating layer protects the tree’s innermost layers from cold while defending against insects.  A tree’s bark also maintains the tree’s moisture balance; it does this by keeping out unneeded moisture during rainstorms while holding onto moisture during drier seasons.

Inner Bark (Phloem)

Phloem Westchester Tree Life

The second later after the outer bark is the inner bark also known as the Phloem.  This layer serves as the pipeline through which food is passed.  The tree’s Phloem lives for a short period of time before it dies and turns into cork, becoming another layer to protect the tree.

The Cambium Cell Layer

Cambium Tree Westchester Tree Life

The green part of this tree’s branch is the Cambium layer.

The growing part of a tree trunk is the Cambium Cell Layer, which new bark and new wood annually in response to the tree’s hormones.  These hormones, also known as Auxins” stimulate growth in the tree’s cells, and are produced by the leaf buds at the ends of the branches during the spring.

Sapwood

Anatomy of a Tree Trunk Westchester Tree Life

Sapwood acts as the tree’s pipeline for moving water up to the leaves.  A tree’s sapwood is new wood; as new layers of sapwood are produced, the inner cells lose their vitality and become heartwood.

Heartwood

Tree Anatomy Westchester Tree Life

Heartwood lies at the center of the tree; it is the central pillar supporting the tree.  Heartwood is a composite of hollow, needle-like fibers bound by the tree’s natural chemical glue, lignin.  Although heartwood is as strong as steel, it is in fact dead.

Is your tree in need of professional inspection or care?  Call Westchester, New York’s best tree care professionals, Westchester Tree Life at (914) 238-0069 or visit us online at westchestertreelife.com!