What is Bark? Botanical Description, Chemical Composition, and Uses

by Joost Nusselder | Last Updated:  May 28, 2022

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Bark is the outermost layer of a tree or shrub, made up of a complex tissue called “dentinal tissue.” It serves as a protective layer covering the wood of the tree and consists of two parts: the inner bark and the outer bark.

In this article, I’ll provide a comprehensive understanding of bark, including its unique structure, form, and function. Additionally, I’ll share fascinating facts about this remarkable component of trees.

What is bark

The Unique Structure and Form of Bark

Bark is a key part of the natural structure of woody plants, providing a protective layer that covers the wood. It consists of two parts, the inner bark and the outer bark, and is composed of a complex type of tissue that is unlike any other part of the plant. Plants with bark include trees, woody vines, and shrubs, and there are many different types of bark, each with its own special characteristics.

The Parts of Bark

Bark is composed of several layers, each with its own unique function. The outermost layer is called the cork layer, which is normally arranged in a pattern of smaller, thick-walled cells. This layer is responsible for protecting the plant from extreme temperatures, drying out, and other environmental stresses. The next layer is called the phloem, which is responsible for transporting nutrients and other molecules from the leaves to the rest of the plant. The innermost layer is called the cambium, which is responsible for the thickening of the bark and the production of new cells.

Differences in Bark

There are many different types of bark, each with its own unique characteristics. Some types of bark, such as the leather-like bark of the cork oak, are considered valuable for their commercial uses. Other types of bark, such as the rough, scaly bark of the white oak, are more typical of local trees and are used for their aesthetic value. The thickness and texture of bark can also vary depending on the species of tree, with some trees having smoother bark than others.

Bark and Style

Bark is often included in the style of a garden or landscape design. The unique texture and form of bark can add visual interest and contrast to a planting scheme. Some designers even use bark as a focal point, creating a feature out of the natural patterns and colors found in different types of bark.

What’s Inside the Bark?

Bark is composed of a variety of structures and tissues that serve different functions in plants. The chemical composition of bark includes:

  • Cellulose and hemicelluloses: These primary structural units are associated with sugars such as glucose, galactose, mannose, arabinose, and xylose.
  • Lignin: This is a complex organic polymer that provides additional structural support to the plant.
  • Suberin: This is a waxy substance that covers the walls of cork cells and protects the tree from water loss and fungal degradation.

When Bark is Damaged: The Importance of Damage and Repair

Bark damage can be caused by a variety of factors, including:

  • Physical damage from animals, humans, or machinery
  • Environmental factors such as frost, sunscald, or drought
  • Disease and fungi targeting the bark

Preventing Bark Damage

To prevent bark damage, it’s best to consider the following:

  • Plant trees in areas where they can grow without trouble
  • Provide proper care for the tree, including watering and fertilization
  • Consult with a professional arborist for advice on tree care
  • Remove any nearby trees that may be infected with disease or fungi
  • Use BioAdvanced concentrate to target and prevent fungal growth

Repairing Damaged Bark

If your tree has already suffered bark damage, there are a few things you can do to help repair it:

  • Remove any loose or peeling bark around the wound
  • Clean the wound with water and a soft brush
  • Apply a tree wound dressing to the wound to prevent infection
  • Consider using a tree wrap to protect the wound from further damage

The Importance of Bark Health in the Forest

Bark health is crucial to the overall health of the forest. When trees are healthy, they are able to grow and thrive, providing habitat for wildlife and helping to clean the air we breathe. However, when trees are damaged or diseased, they can become a danger to nearby trees and wildlife. By taking care of the bark on our trees, we can help ensure the health and vitality of our forests for generations to come.

From Cork to Medicine: The Versatile Uses of Tree Bark

The outer bark of trees may seem like just a protective layer, but it has a variety of uses:

  • Cork: The outer bark of cork oak trees is harvested and used to make cork products such as wine stoppers, bulletin boards, and flooring.
  • Extracts: The bark of certain tree species, such as the cinchona tree, is used to extract quinine, a medicine used to treat malaria.
  • Living Bark: The outer bark of living trees can be stripped and used for tanning leather or making baskets.

Inner Bark: A Medicinal Marvel

The inner bark of trees is often overlooked, but it has many medicinal properties:

  • Birch Bark: The inner bark of birch trees contains betulinic acid, which has anti-inflammatory and anti-cancer properties.
  • Willow Bark: The inner bark of willow trees contains salicin, which is similar to aspirin and can be used to treat pain and fever.
  • Commercial Uses: The inner bark of some tree species, such as the slippery elm, is used to make commercial products such as throat lozenges and digestive aids.

Bark as a Surface: More Than Just Texture

The surface of tree bark can be used for more than just its interesting texture:

  • Paintings: The bark of some tree species, such as the paper birch, is used as a surface for paintings and drawings.
  • Map Making: The bark of some tree species, such as the mulberry tree, is used as a surface for making maps.
  • Landscape Mulch: The bark of trees can be used as a natural and attractive mulch for landscaping.

In conclusion, tree bark is not just a protective layer, but a versatile material with a variety of uses. From cork to medicine, inner to outer bark, and even as a surface for paintings and map making, the bark of different tree species has been utilized in many ways throughout history.

Smoking with Bark: To Do or Not To Do?

When it comes to smoking meat, the bark on the wood plays an essential and unique role in producing a good result. The bark consists of compounds that offer a variety of ingredients that add to the flavor of the meat. The dry process of smoking requires a balanced handle of the material to produce the optimum result.

The Benefits of Using Bark

Despite the fact that some people prefer to remove the bark, research explains that leaving it on can significantly affect the flavor of the meat. Here are some benefits of using bark while smoking meat:

  • It produces a hot and clean burn, which is helpful in creating a balanced flavor.
  • The bark offers a long burn time, which is excellent for smoking meat for a couple of hours.
  • It helps to control the temperature and offers a chance to produce the right amount of smoke.
  • The bark forms a protective layer around the wood, which helps to prevent excess fat from covering the meat.
  • It offers additional benefits like producing a unique flavor and aroma that is synonymous with barbecue.


Bark is the protective layer of a tree or shrub made of different types of tissue. It protects the woody tissue beneath from physical damage, environmental factors, and disease. Bark can be rough or smooth, thick or thin, and come in many different shapes and colors. 

It’s important to know the differences between the types of bark and their special characteristics so you can care for your trees properly. So, don’t be afraid to ask questions and get the answers you need.

Joost Nusselder, the founder of Lakeside Smokers is a content marketer, dad and loves trying out new food with BBQ Smoking (& Japanese food!) at the heart of his passion, and together with his team he's been creating in-depth blog articles since 2016 to help loyal readers with recipes and cooking tips.