Burls and Other Unusual Woods
Nature Bulletin No. 629-A February 19, 1977
Forest Preserve District of Cook County
George W. Dunne, President
Roland F. Eisenbeis, Supt. of Conservation
BURLS AND OTHER UNUSUAL WOODS
Wood worked by the hands of skilled craftsmen puts a wealth of quiet
beauty into our daily lives. The warm glow of natural wood in different
shades and forms invites the touch and a home without it seems drab
and artificial. Most carpenters and amateur handy men are happy to
work with straight boards with straight grain sawed from perfect logs.
In contrast, the finest paneling, cabinetwork and art objects in wood
are made from parts of the tree which are ordinarily discarded. The
crooked grain in stumps, and logs with knots or crotches, yields
fanciful patterns when turned on a lathe or cut into veneer. So does the
twisted grain in trees crippled by old injuries and in the tumorous or
abnormal growths called burls.
The appreciation of woods with irregular grain is not new. Very fine
pieces of furniture decorated with veneer cut from rare and precious
burls have been found in ancient Egyptian tombs. One of the prize
exhibits in the Metropolitan Museum of Art in New York is a bed
taken from the tomb of the great-grandparents of King Tut's wife
which is paneled with veneer of laburnum and acacia. It is not known
how they sawed these thin layers or how they prepared glue that still
holds after 3500 years.
Sometimes a burl is defined as an enlarged bump growing on a tree
trunk and sometimes as almost any unusual woody growth. They are
found occasionally on a wide variety of trees. Certain large galls or
burls on oaks follow a chronic fungous infection. On other trees they
seem to result from injuries, burns or continued irritation. In most
cases the causes are not understood.
A smoker becomes attached to his brier pipe. He fondles it, guards it,
and rubs it on his nose to bring out the grain in the wood. Ordinarily
the bowls of these pipes are made from brierwood -- the gnarled roots
of the tree heath, a dwarf tree that grows in France, Italy and Algeria.
During the World War II, when imports of brierwood were cut off,
American pipe manufacturers turned to root burls from such native
members of the heath family as the mountain laurel and rhododendron
of the southern Appalachians and the manzanita of California. Since
then burl blocks by the millions, each large enough for one pipe bowl,
have been cut from these woods.
Many kinds of trees produce the lumpy swellings called burls but those
of the redwood may be six or eight feet thick and weigh thousands of
pounds. Their heavy hard dark wood is figured with a fantastic grain.
Like the potato with its eyes, a burl contains buds. A small one from
the redwood placed in a dish of water will send up a ferny sprout.
Hundreds of tons of burls from redwood, myrtlewood, madrone, and
western maple are exported annually from Oregon to France and Italy.
Strangely enough, much of the fine furniture veneer made from these
burls is returned to the United States.
walnut and black cherry burls are highly prized both because of
the rich colors of their woods and because of their weirdly distorted
grain. This is produced by innumerable buds that failed to develop,
giving a bird's-eye effect. Rare sugar maple logs -- perhaps only one in
a hundred or a thousand -- shows the exceptional curly or bird's-eye
pattern in the grain. It is not strictly a burl but good examples are
extremely valuable and at one time was preferred above all other
woods for fancy gun stocks.
Tastes in woods change like fashions in hats. Pine boards full of knots
and cypress boards full of holes, once worthless, now bring high prices
for paneling in dens and rumpus rooms.
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Update: June 2012