eGarden © 2007 Ed Mues

Not as Rare as Ives ... Burl, That Is

You might know by now that I enjoy all kinds of music (Burl Ives, included). In an earlier column I wrote about when I was proprietor of a plant store in New York City. I told of a traveling vendor who sold burls of the famous California redwoods.

I purchased and resold many redwood burls in those early years. Placed cut (flat) side down in a dish of water, the hidden, adventitious buds produced a wonderful sprouting of airy, bright green growth that was lovely and mysterious to behold.

The more glamorous the container of water, the more majestic the presentation. It was a wonderful centerpiece for a table setting. The mystery was unfathomable. No roots anywhere. The fern-like growth was feathery soft, just like new redwood tree growth. Even the pine-like resin aroma was there.

Burls have been a fascination of mine for a long time. I first wrote about galls in 1998, and it was at this same time that I knew I had to explore burls because there were some close resemblances. So close, that some experts and other observers thought they were related. Turns out, I think they're not. But, there is still a swirl of controversy and confusion, because they are so little understood. This just makes it more interesting.

The burl has been described by a variety of terms: enlarged bump; unusual woody growth; outgrowth; wood galls; root gnarls; lumpy swellings; abnormal growths; woody excrescence or protuberance; wart-like deformed growth on trunk, root, or branch of a tree; tumors on wood; the result of a massive, haphazard growth of cells; an overgrown knot or excrescence; occasional irregular spherical growths on trees; abnormal growth bulge; and spherical woody growths.

The general consensus is that burls are the result of a complex growth response to what are commonly known as environmental insults. These include injury from lightning, infection, freezing, bud growth demise, fire, and mechanical injury. On another, more microscopic level, also, any irritation of the cambium layer by bacteria, fungi and possibly viruses.

The cambium layer is where new layers of wood and inner bark are produced. The mystery comes from the fact that so much can be deduced from the growth and structure of the burls, and yet, because the burls take so long to grow and reach anything near maturity, it's another generation that has to check out the earlier subject and the accompanying statistics. Many burls are nearly as old as the trees on which they grow.

Interest in these unusual, but not rare, growths on trees, their branches, and even roots is not recent. Insatiable curiosity is a gift given man at birth. It's not hard to imagine an observer wondering about the nature of these odd appearances, and the result was further exploration and learning. Irregularly grained woods, often discarded today by lumber manufacturers and processors, offer something of unusual rarity in their rippled grains and tortuous patterns. The experienced craftsman can transform unusually grained woods into beautiful and extraordinary works of utility and art.

You might be surprised to learn that ancient Egyptian tombs have yielded exceptionally fine furniture that included veneers from rare and exotic burls. It remains a mystery how these were cut into such thin layers and how a cement to bond these layers to the wood has held for 3500 years.

After examining all of the possible environmental insults, including the nail in the tree, the larvae eating into the cambium layer, the chronic fungus infection, even the barbed wire grown over and now deeply embedded into the tree, it is still unclear why the tree's response is as it is. If the gall comparison has any validity, I'm led to believe that, just as in gall formation, the tree compartmentalizes the source of irritation. It seems to do this by changing the cell division rate in the cambium layer. Lots of xylem tissue is produced, and the grain is contorted.

In the second paragraph I used the term "adventitious buds". Adventitious buds are accidental, extra, and out of the normal buds. It is believed that a burl originates in a single cell near the pith. As it enlarges and continues to grow it produces numerous buds that never fully develop or mature. Just as a potato has many eyes, so a burl has many buds.

Upon examination, the wood grain of many burls swirls around each bud trace. It is this little understood response of nature that makes some burls so interesting and beautiful. "Bird's eye" in maple resembles the eye like features in many burls, but is not the wood of a burl at all. It I still heavily sought after, as is much "figured" wood, as it is known.

But, in spite of all the seeming insults, burls often do not appear at the more likely sites. Curiously, where burls do appear, they seem to appear in greater numbers over that specific area. Other nearby areas may have no burl growth in evidence. This increases the mystery and the search for the perpetrator, if that word is appropriate. Burls seem to cause no injury to the trees on which they grow. The trees usually remain healthy and grow for many years without harm. Now and then a burl will become too large and heavy for the tree to successfully support, and stresses ensue that cause the tree to begin to suffer.

Burl wood is very hard, but not very strong. This is the result of the irregular growth pattern of the grain. Burls do furnish a unique medium for the arts and crafts industry. Long ago pipe smokers especially valued pipes made from brierwood, the root burls of a dwarf tree in the heath family that grows in France, Italy and Algeria. Today's brier pipes are made of native mountain laurel and rhododendron root burls as well as those that form on manzanita roots from California.

The largest burls are found on the redwoods, some weighing many thousands of pounds and being several feet thick and high. Hundreds of tons of burlwood are exported annually. Much of it comes back to America as furniture with fine veneers of the same burlwood after being cut and processed in Italy and France.

There are several specialized dealers of burlwood that are easy to find for anyone with a computer. Prices are according to rarity and the market forces. I'm happy to tell you that the most prized burls are found on black cherry, sugar maple, redwood and black walnut. If you come across any of these and know a woodworker, have some sliced and sanded. Once smooth, a light coat of oil will bring out the beauty. Enjoy the picture!

From The Garden of Ed. Submitted for publication in The Towne Crier on April 4, 2007

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