What are wood burls?
A burl is the abnormal growth of a tree associated with some environmental stress. Burls are believed to be the result of an insect infestation, fungal, bacterial or viral infections or physical damage from lightening, logging or natural tree-fall. They usually take the shape of a bulbous mass or protrusion near the injury, although they can sometimes form in the root system below ground level.
Why are wood burls desirable?
In contrast to its homely exterior, the inside of a wood burl is a wondrous thing. Wood burls are, simply put, everything that make fine wood special distilled into a single, gorgeous package. They invariably contain the most complex and intriguing grain patterns found in all of woodworking, including (but not limited to) blister, curly and bird’s eye figures. Indeed, it is not uncommon to find every one of these covetable elements incorporated into a single burl. Predictably, this makes burls visually stunning, particularly when combined with a boldly colored wood.
How are wood burls used?
Burls are employed anywhere a relatively small, aesthetically appealing wood surface is desired. Furniture will often incorporate thin burl veneers to cover larger areas cost effectively. But smaller items such as jewelry or valet boxes, fountain pens, turned bowls, objets d’art and custom knife and gun handles can be made from solid wood burls. Basically any wooden luxury item can be fashioned from burl, provided the end customer is willing to pay the often substantial price tag.
Working with burls is a delicate process and high wastage is commonplace. Because of their irregular formation, it isn’t unusual for wood burls to be full of voids, sap pockets, silica, bark and even rocks (for root burls). This makes the woodworker’s job very difficult. Exceedingly sharp tools made of super hard alloys help prevent tear-out due to the highly figured, interlocking grain. But years of experience are the best ally of the craftsman who wants to fashion raw burl into a woodworking masterpiece.
Why are wood burls so expensive?
The answer to this question is fairly simple – because they are rare and in extraordinarily high demand. Wood burls only form unpredictably from anomalous situations – an insect infestation, physical trauma, etc. Therefore, there is a substantial element of chance in their formation.
In addition, many tree species are not naturally predisposed to the formation of burls. If these species should suffer the injuries mentioned above, they will more often than not simply die without forming a burl at all.
Burl’s unusual origins mean that it cannot be successfully cultivated via plantation-style tree farms. Many species of commercially important lumber trees – teak, mahogany and pine, for example – have been adapted to tree plantations where their growth can be specifically regulated and accelerated. But it isn’t possible to reliably stress a tree in the proper way to ensure the creation of a burl. In most instances, you would just kill the unfortunate tree.
Therefore, burls are only created in nature by happenstance and then discovered by dedicated loggers who must slog through dense forests, steep mountains and remote wilderness to secure them. Given the difficulties in procuring them, it is a wonder that wood burls are as widely available in today’s marketplace as they are. However, with mankind’s continued destruction of forests and other natural habitats, this relatively widespread availability might not persist.
Types of wood burls
As mentioned above, some tree species are naturally predisposed to the creation of burls while most are not. I have listed below the kinds of trees that commonly form burls, which also makes them the most frequently encountered wood burls in a commercial setting. This list is meant as an overview only, however, and is undoubtedly incomplete. In addition, it is occasionally possible to find wood burls for sale from species that do not normally produce them. Those tree species, of course, will not be covered here.
Walnut Burl
There are actually several different species of walnut that tend to form burls: English Walnut (Juglans regia), Black Walnut (Juglans nigra) and Claro Walnut (Juglans hindsii). English Walnut’s natural range extends from Eastern Europe to Western Asia, while Black Walnut is native to the Eastern United States. Claro Walnut is a closely related species found exclusively in Oregon and California.
Walnut burls, with their rich chocolate tones and wild figuring, are among the most desirable of wood burls. They have been used in Europe for hundreds of years in high end furniture and wood turning. Indeed, it isn’t uncommon to find 18th century Georgian and 19th century Victorian antiques that lavishly employ walnut burls in both veneer and solid form.
Carpathian Elm Burl
English Elm (Ulmus procera) is a large tree found in Western Europe that features light reddish-brown wood. English Elm is often referred to as Carpathian Elm when it comes in burl form, even though these are really the same species. This type of burl most commonly comes in veneer form with solid material being rather scarce. The grain patterns on Carpathian Elm burl usually consist of very tightly packed bird’s eye elements caught in swirling eddies.
Black Cherry Burl
A deciduous hardwood from the Eastern U.S., Black Cherry (Prunus serotina) timber has been prized for centuries for its superior workability and glowing, reddish-brown patina. Although it is fairly widespread from a geographical perspective, Black Cherry trees reach their largest dimensions in the primeval Appalachian forests of central Pennsylvania.
Cherry wood’s almost legendary status is elevated even further when found in its rare burl form. Bird’s eye elements and gently meandering grain patterns accentuate the wood’s naturally rich rose tones. When cherry burl does come on the market it is invariably scooped up by experienced woodworkers for turned bowls, knife scales and other fine woodcrafts.
Although the Black Cherry species dominates the cherry lumber trade, its smaller European cousin – Sweet Cherry (Prunus avium) – yields very similar burl material on occasion.
Buckeye Burl
The Buckeye (Aeculus octandra) is a rather unusual tree, at least from a woodworker’s perspective. This medium-sized deciduous tree is a resident of the Eastern United States. But its wood is a boring, creamy-white color with little in the way of interesting grain features. In addition, its timber is soft and weak, making it ill-suited for most structural purposes. Under most circumstances, Buckeye wood has no commercial use.
Buckeye burls, on the other hand, are an eye-catching kaleidoscope of intense blue-blacks contrasted against golden-tinted ivories. Buckeye is a root burl, meaning it often contains irregular void pockets, along with sand and small rocks. In spite of this, wood-loving craftsmen cherish this burl for its unique color palette and amazing grain patterns.
Redwood Burl
Redwoods (Sequoia sempervirens) are renowned coniferous denizens of the California coast, towering up to 300 feet (90 meters) tall with diameters of as much as 12 feet (3.7 meters). Redwood lumber is renowned for its ability to weather the elements, making it a natural choice for decking and outdoor furniture.
But it is Redwood burl, with its impossibly intricate lace patterns and intense reddish hue, that has really captured the modern imagination. Because Redwoods are among the world’s largest trees, it isn’t uncommon for their wood burls to be absolutely massive. This makes it possible to occasionally find solid burl slabs large enough to fashion into dining tables or other large showpieces. A large slab of Redwood burl can easily go for more than $1,000 on the open market.
Unfortunately, the high prices and unflagging popularity of Redwood burls have prompted poachers to illegally harvest the wood from trees located in protected national and state parks. Of course, reputable lumber dealers will not touch these poached goods.
Bigleaf Maple Burl
The Bigleaf Maple (Acer macrophyllum) is a variety of soft maple that grows in the Pacific Northwest of the U.S. and Canada. This impressively large tree reaches sizes of up to 100 feet (30 meters) tall with a diameter of up to 3 feet (1 meter). Bigleaf Maple timber is considered a good all-purpose wood, albeit somewhat visually boring. Consequently, it is fairly low in price.
All that changes when we start talking about maple burls, though. Instead of an uninspiring beige or white color, Bigleaf Maple burl sports an array of colors ranging from orange to coral to golden-cream. In addition, it is sometimes possible to acquire spalted maple burl, which is wood that has been exposed to fungus. This creates wildly contrasting grain patterns lain overtop the already mentioned sumptuous colors. Bigleaf Maple burls also commonly come with live edges, which skillful woodworkers can exploit to create artistic masterpieces.
Madrone Burl
The Madrone (Arbutus meziesii) is a medium-sized broadleaf evergreen tree endemic to the U.S. Pacific Northwest. This tree goes by several other names, including Madrona, Pacific Madrone and the rather whimsical Strawberry Tree.
Plain Madrone wood isn’t often used in woodworking because it is subject to severe warping. However, its hard, dense root burls are in perpetually high demand from knowledgeable woodworkers. They are not only magnificently figured, but also sport delicately cream-colored wood with pink to light red overtones, which makes for a visually stunning wood burl.
Myrtle Burl
Myrtle (Umbellularia californica), otherwise known as Oregon Myrtle, Pepperwood or California Bay Laurel, is a medium-sized evergreen hardwood native to California and Oregon. Plain Myrtle wood is easy to work with and finishes well, a real bonus when combined with its striking range of colors.
Those marvelous colors – honey yellows, butterscotch browns and dulcet oranges – make Myrtle burl particularly appealing. It is even possible to find Myrtle burl that sports wild black or violet highlights. These unique color combinations are the result of slight variations in the mineral content of the soil the trees grow in.
Myrtle burl is incredibly expensive for a domestic hardwood, but might just be the perfect burl for the woodworker who wants to try something a little bit different!
Eucalyptus Burl
Almost all eucalyptus trees are native to Australia, where almost 700 different species in the genus reside. Despite this genetic diversity, eucalyptus wood tends to share certain physical similarities that make it an excellent general purpose lumber. These include high density, excellent hardness and good strength.
Eucalyptus burls, however, take these desirable physical properties and supercharge them with magnificent resin veining, bird’s eye figuring and crotch patterns. Although the eucalyptus genus as a whole is susceptible to forming burls, certain species are particularly noteworthy.
For example, Jarrah (Eucalyptus marginata) – a eucalyptus found in southwestern Australia – is renowned for its deep burgundy color and the incomparable figuring of its burls. For those who are interested, I recently featured an outstanding contemporary Jarrah burl watch box in the Spotlight section of my website.
River Red Gum (Eucalyptus camaldulensis) is another well known reddish eucalyptus burl, although it usually isn’t as strikingly figured as Jarrah burl.
Yellow Box (Eucalyptus melliodora) forms desirable burls with a characteristic, yellowish-cream to golden-brown color.
Red Box burl (Eucalyptus polyanthemos) is the final eucalyptus burl commonly encountered. Burls from this species can be an intense brownish-red, making it a favorite of woodworkers looking for the perfect color for that special project.
There are, of course, many other eucalyptus burl species not mentioned here. And woodworkers interested in Australian burls should note that pockets full of sand, dirt and rocks are fairly common hazards. Even so, the stunning beauty of eucalyptus burls makes them well worth the effort.
Thuya Burl
Thuya (Tetraclinis articulata) is one of the more interesting and exotic trees in our list. Native to the remote Atlas Mountains of Morocco, this relatively small coniferous tree is a member of the Cypress family – Cupressaceae. Thuya wood has been used since ancient times, and was highly prized by both the Greeks and Romans for its pleasant fragrance and mesmerizing orange-brown to red-brown root burls.
In fact, Thuya was purportedly used – along with the famous cedars of Lebanon – to construct King Solomon’s Temple in Jerusalem. In the 1st century BC, the famous Roman politician Marcus Tullius Cicero bought a Thuya burl table for the princely sum of 300,000 denarii. This sum was more than 1,300 times the annual salary of an average Roman solider.
Today, Thuya burl is becoming much scarcer because of the tree’s limited geographical range and widespread deforestation. As a result, Thuya burls are typically only available in small sizes.
Amboyna Burl
Amboyna burl is actually derived from multiple tree species in the Pterocarpus genus, most notably the Narra tree (Pterocarpus indicus) and Burma Padauk tree (Pterocarpus macrocarpus). These tropical hardwoods grow in the rainforests of Southeast Asia, Indonesia and Borneo.
Amboyna burl first came to the attention of Europeans in the late 18th century, when the colonial powers in Southeast Asia began to import it into Europe in quantity. It quickly became one of the world’s most favored burl woods – a title it still retains. Today, Amboyna burl is often used for the interior trim of ultra-expensive luxury cars like Bentleys and Maybachs.
Demand for Amboyna burl has been so strong that it can be difficult to source in larger sizes due to overharvesting. Expect to pay egregiously high prices when you do manage to find any, regardless of its size.
Amboyna burls range in color from a light, honey-gold to a strikingly rich red. It also displays wonderfully complex figuring, including bird’s eye, crotch and blister patterns. No wonder Amboyna burl is the most prized wood burl on the planet!
Camphor Burl
The Camphor tree (Cinnamomum camphora), or Camphor laurel as it is sometimes known, is a tropical hardwood found in Southeast Asia. This is another one of those trees where the plain wood is considered below par in the woodworking world. It isn’t as strong or hard as many tropical hardwoods and has a fairly mundane, light brown color that is often mixed with rather unattractive olive or gray tones. Because of this, plain Camphor wood is rarely exported for commercial purposes.
Camphor burl, however, is a completely different animal. Here the wood takes on a much more vivid golden-brown color complemented by intense curly figures interspersed with bird’s eye patterns. Camphor burl is commonly available in both veneer and solid burl forms, and is often used for electric guitar tops. One unusual fact about Camphor wood is that freshly worked material smells strongly of root beer!
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