The burl of a tree, an outgrowth of the tree

You may have heard of it or seen products carved from birch burl, elm burl or olive ash burl in our store. This article will explain what a burl is, why it is formed and how it is used.

Anne-Laure CompainAnne-Laure Compain

Anne-Laure Compain

Nature Lovers
Published on 17 May 2023 (Updated on 6 October 2023) birch burl

The wooden burl, an unexpectedly beautiful gift of nature

Before I explain what a wood burl is, let me go back to the definition of the term. In the dictionary, it says that a burl is "a gnarled, rounded growth of a tree, used especially in crafts and veneers."

The burl of a tree is a growth that can be found on the trunk or branches and that forms as a result of a stress that the tree undergoes. The burl is a reaction of the tree to protect itself from an external aggression.

It is also possible to find burls at ground level but they are confused with roots.

You cannot say that a burl is a tree disease because, even if a tree has formed a growth on its trunk or branches, it can continue to live for years. When you see it, you may think that the tree is sick, but it is not!
formation of a burl on a birch tree

Beyond the bark: discovering the creation of tree burls

From the outside, the burl looks like a bump on the tree, it is very recognizable. The size of a burl varies according to its age and the tree on which it was formed. If we take the example of the redwood, some burls formed on this large tree can reach 8 meters and encompass the entire trunk of the tree (see photo below).

Inside, the wood of the burl of a tree has the shape of intertwined circles. By cutting a burl, you can see that this wood has formed into circles and that the layers have merged in some places.

burl on the trunk of a redwood
appearance of a redwood burl

How is a burl formed on a tree?

Today, we do not know exactly how this growth is formed on the tree. We have to wait for nature to do its work and for the tree to form the burl and then harvest it. If we knew how a burl is formed, there would be tree farms all over the world to grow burls by the hundreds. But this is not the case and that is why it is a rare, highly prized and expensive raw material.

burl and its bark on a tree

Why does a burl form on a tree?

If we don't know how a burl forms, we know why it forms! This outgrowth is a defense mechanism of the tree in front of the stress that it undergoes. This stress can be due to multiple factors such as infections caused by insects or fungi, a wound in the bark or the development of mistletoe parasite.

Once the defense mechanism is triggered, the normal growth process of the tree is disrupted. Indeed, the unopened buds will accumulate on top of each other, forming the burl.

The bark on the burl, like the rest of the tree, protects the wood.
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The art of nature for the happiness of wood craftsmen

The burls are a gold mine for the wood craftsmen and a raw material for the manufacture of furniture and high-end objects. It is important to know that a burl is unique, you will not find two burls with the same appearance. When you start carving in a burl, you don't know what patterns and colors it will offer you.

What can be done with burl wood?

Here is a list of some of the possible uses of the burl. But really, the only limit is your imagination!

  • Inlaying burl wood to decorate cabinets, tables or musical instruments
  • Creation of wall panels or doors inside the house
  • Creation of vases, cups, bowls or dishes in wood
wooden box of burl of thuya
cedar burl guitar
coffee table in burl wood
chess set in burl of thuya

Discover the unique Kuksa Shop wood products hand carved in burl

Birch burl

Authentic Finnish wooden cups, called kuksa, carved from birch burr and decorated in some cases with a piece of reindeer antler. We also offer an assortment of birch burr spoons.

kaniini kuksa in birch burl The birch burl

Olive ash burl

The olive ash burl offers incredible shades of brown and allows us to carve butter knives, bowls but also coasters and key rings.

knife, bowl and coaster in olive ash burl The olive ash burl

Elm burl

Creation of wooden cups, knives and spoons in elm burl to enjoy a breakfast in 100% natural tableware. We also make elm burl coasters and key rings.

cup and bowl in elm burl The elm burl

The most sought-after burls for woodworking

Burls can grow on many varieties of trees but here are the most common:

  • Elm
  • Oak
  • Ash
  • Birch
  • Walnut
  • Maple

As an example, here is what a raw birch burl looks like when carved in kuksa:

appearance of the birch burl
interior appearance of the birch burl
birch burl kuksa
corne de renne kuksa authentique

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