Types of Burl Wood: Species, Values and How Burls Form

The types of burl wood are named by the tree they grow on, such as walnut, maple, redwood, amboyna and thuya, and by where on the tree they form. Wikipedia defines a burl (burr in British English) as a deformed growth in which the grain has grown abnormally, the result of hyperplasia, a greatly abnormal proliferation of wood cells by the cambium. It appears as a rounded outgrowth on a trunk or branch, filled with small knots from dormant buds, and Wikipedia notes many burls grow below ground on the roots.

The trigger is some form of stress: injury, a virus, a fungus, or a bacterium such as Agrobacterium tumefaciens (Wikipedia). Carved lists insect attack and constant soil pressure on roots among the causes. GL Veneer notes that the exact process is still not fully understood. The wood inside is sound; the swirls and "eyes" are what buyers pay for.

Carved, a wood-products maker, sorts burls this way:

• Root burl - at the base of the tree or below ground; the densest, most intricate grain.
• Trunk burl - large, with varied swirls and eyes.
• Limb burl - smaller, with complex grain.
• Birdseye burl - small circular eyes scattered through the wood. Wikipedia distinguishes birdseye maple, a figure in sugar maple, from true burl.
• Spalted burl - fungus has added dark lines and color patches.
• Cluster burl - several burls grown together into one mass.

Veneer mills GL Veneer and Oakwood Veneer, the Wood Database and Wikipedia describe these as the main commercial burls:

• Walnut burl - warm brown clusters and swirls; the classic furniture burl. Black walnut
• Maple burl - light-toned with tight eyes; Wikipedia gives "burr maple" as an example. Hard maple
• Redwood burl (vavona) - rich red-brown from California coast redwood; the largest burls of any tree. Redwood
• Amboyna - the burl of narra (Pterocarpus indicus) and related species, named after Ambon Island in Indonesia; red or golden. The Wood Database calls it one of the most expensive and sought-after burls.
• Thuya - root burl of Tetraclinis articulata from the Atlas region (mainly Morocco), with a cedar-like smell; plain thuya wood has little commercial value (Wood Database).
• Mappa burl - browns, yellows, reds and blacks in high contrast (GL Veneer).
• Madrone burl - soft warm tones from western North America.
• Carpathian elm burl - bold patterns from European elm.
• Karelian birch - rippled figure with dark streaks, from Finland and Russia.
• Imbuia, chestnut, olive ash, oak and eucalyptus burls - also sold as veneer by the same mills.

Carved adds cherry, buckeye and bigleaf maple burls, which turn up in live-edge work.

There is no public price index for burl wood, so treat any single number with care. What the sources we opened say:

• Carved (accessed 2026-09-25) puts burls at anywhere from a few dollars for small pieces to several hundred or several thousand dollars for large, high-quality ones.
• Wikipedia notes burls may reach high prices on the wood market because of their beauty and rarity.
• The Wood Database describes amboyna as among the most expensive burls, usually sold as veneer or small turning blanks because of its value, and says thuya prices are very high, especially for pieces with many tightly packed eyes.
• GL Veneer grades burl veneer as Regular (more swirl, less symmetry), Premium and Architectural (the "jewelry box" grade with near-perfect symmetry).

The features that raise value are consistent across these sources: species (amboyna and thuya at the top), size, density of eyes, and sound wood without voids or rot. If you have a burl to sell, get the species confirmed first; a photo of a sanded face in WoodLens is a quick start.

Burls are uncontrolled growth, which is why they are sometimes loosely compared to tumors, but the sources we opened do not describe them as a common cause of tree death. The bigger risk comes from removing one. Wikipedia describes poachers cutting burls from ancient coast redwoods in western US national parks, sometimes felling whole trees, and notes that the cuts expose the wood to infection and disease. Legal burl comes from salvaged timber on private development land and from lumber companies with proper permits.

So: never cut a burl from a tree in a park or on land you do not own, and on your own tree, ask an arborist before removing a large one from the trunk.

Wikipedia notes the interlocked, knotty grain makes burl extremely hard to work with hand tools, though that same toughness made it valued for bowls and mallets. Oakwood Veneer adds that burl is dense and durable but can be brittle during processing. Wikipedia lists furniture, veneer, musical instruments and woodturning as its main uses, not structural work.

This page was drafted with AI help, and every fact was checked against the sources listed on the page.