Vavona Burl Comes From Mighty Redwood.
Vavona burl is so exotic looking it is hard to believe it originates from the massive root area of what is commonly called sequoia. In A Natural History of Western Trees, Donald Culross Peattie writes that the tree's "enormously swelled bases are buttressed with great lynch-like claws, as if the trees gripped the earth to keep their balance.. The effect of gigantism is increased by the burls often seen on the trunks. Many other kinds of trees also produce those lumpy swellings but the redwood's burl are in proportion to the rest of the tree -- as much as six and eight feet thick."
Unknown Origins of Burls
While burls can occur with all species, redwood trees seem to have a higher occurrence of burls than other species. No one knows for sure what causes a burl to form, but Albert Constantine Jr. theorizes about them in Know Your Woods.
"A burl is an abnormal, wart-like excrescence on the trunk or branches of a tree," Constantine writes. "Examined closely, it may appear to consist of a great mass of 'eyes' or dormant buds. The surface of such a bulge may be smooth or rough. In either case, the alignment of the fibers is very irregular and the burl is gnarled. Because of this, many bizarre figures are derived from veneers cut from burls. Causes of burls are imperfectly understood and the following reasons have been advanced to explain this unusual growth: injury from frost, fire or mechanical contact; and irritation of the cambium by bacteria, fungi, and possibly viruses."
Constantine adds that a popular legend is that woodpeckers knocking at the trees create "wounds" that are the cause of burls. He says the theory is discredited because burls happen in areas without woodpeckers.
Culross Peattie likens burls to the eyes of potatoes. "A burl contains buds, and the small burls sold by the roadside will, if you put them in a dish of water, send out a ferny sprout."
Good Turning Wood
Veneers, a Fritz Kohl Handbook, from Interwood Forest Products, lists the main use for vavona burl as high quality architectural woodwork. Vavona burls are also popular for turnery purposes. The rest of the redwood tree is used for exterior cladding, shingles, fence posts, signs, decks, outdoor furniture, vat making, coffins and paneling. Because redwood is so resistant to rot, it is a popular choice for uses around water, such as hot tubs and wine casks. Some logs are cut and used for plywood. Bark from the redwood tree is used for making chipboard.
A Domestic with an Exotic Look
The Fritz Kohl handbook describes vavona burl as deep, dark red in color and usually one of two types. One, the lace form, is actually burly wood. The other is the bird's-eye form, which features fine, darkly pronounced dots scattered over the surface and is similar to bird's-eye maple and thuya burl.
California redwood usually has a red-brown heartwood with a distinct growth ring figure revealing the tree's earlywood and latewood zones. The heartwood yields a variety of properties which are dependent on the the tree's growth rate and latewood development. The rest of the tree's wood is a light clear red, but will darken to a darker shade of red after exposure. A single tree yields as much as 480,000 board feet of lumber. The wood has low bending strength, crushing strength, low resistance to shock loads and low stiffness.
California Big Tree
Many experts consider redwoods' close cousin, the Sequoia gigantea, or California Big Tree, to be one of the most impressive trees on earth. These trees live incredibly long lives and have the widest diameters of any trees in the world.
Sequoia gigantea has a normal life expectancy of 1,000 to 1,500 years. Cutting of these redwoods has sparked a great controversy in the United States because so few of the old-growth trees are left. While redwoods once existed all over the Northern Hemisphere, today the trees grow only near the coast of northern California and southern Oregon in a range roughly 500 miles long and 35 miles wide.
The California Big Tree is a protected species. The wood from the trees has little commercial value.
Sequoia sempervirens of the Family Taxodiaceae
Redwood burr or vavona burl is the marketing name for the burls that grow on trees known as California redwood, sequoia, coastal sequoia, sempervirens and palo Colorado.
Trees are some of the tallest in the world and routinely grow between 200 to 340 feet and higher with average weight of 26 pounds per cubic foot.
The wood should be dried very slowly to avoid checking of the surface of the burl. Experts say that slowing the process of drying helps guarantee a good result. Experts also recommend using very sharp cutting tools when slicing burls. Screw joints must be pre-drilled. Vavona burl veneer can be glued satisfactorily. Experts recommend using a clear gloss finish to accent the burl's texture and color. Redwood trees are susceptible to attack by longhorn beetles and pinhole borers.
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|Publication:||Wood & Wood Products|
|Article Type:||Brief Article|
|Date:||Nov 1, 1999|
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