April 10, 1917 



Growth'-Ring Wood Figures 



Ho Maxwell 



Editor's Note 



The rings In a tree's trunk which serve to check ufT its years and furnish a record of 

 its age, are responsible for a large part of the ligured wood employed in the woodusing indus- 

 tries. These figures vary greatly in pattern and intensity, not only in accordance with the species 

 of trees, but also in conformity to the purpose and skill of the man who saws the lumber. The fol- 

 lowing article deals with figures which depend uponthe tree's rings of yearly growtli, and are brought 

 out by the skill of the sawyer, the planing mill operator, and the wood hnisher. 



ARTICLE SEVEN 

 Figured woods are the rule rather than the exception, for not a 

 ■wood grows in the United States which will not show figure of some 

 kind if the surface is sawed and polished. Many such figures are too 

 ■weak and uninteresting to attract attention and they may be kept out 

 of consideration. Figures in wood fall in four general classes when 

 considered with respect to cause and origin. There are almost end- 

 less combinations of this four, but the causes need not be obscured 

 on that account. The origins of the four classes of figures follow: 



EDGE GK.\IN FIGURE 



It can scarcely be called a figure since it consists of parallel lines. It is the 



leading feature of edge grain flooring. 



1. Figures of varying patterns are produced by cutting the rings 

 of annual growth at different angles. Chestnut and ash lumber when 

 dressed always shows growth-ring figures, and usually with dis- 

 tinctness. Practically every other American wood, if cut and dressed, 

 exhibits' figures of the same class, but stronger or weaker according 

 to the sjjeeies. Such figures in basswood, buckeye and eottouwood are 

 weak. 



2. Figure is developed by cutting some woods parallel with the 

 medullary rays, by which the flat surfaces of the rays are exposed 

 -to view. The best illustration of this is in quartered oak. The an- 

 nual ring has nothing to do with that figure, but it may combine with 

 it. Some figure of that kind may be brought out of every wood by 

 sawing logs radially — lengthwise and from bark to heart; but the 

 ma.jority of woods have medullary rays so small and inconspicuous 

 that quarter-sawing does not develop much figure. 



3. Figure of the third class is due to distorted growth. It is best 

 illustrated in birdseye ' maple and curly birch. 



4. Figure is produced by irregular distribution of color, more or 

 less independently of growth rings, medullary rays, or distortions. 

 Tlie .\merican woods which show this figure best are red gum and 



black walnut. Probably the best example of it among all commer- 

 cial woods is Circassian walnut. 



The Ring-Gro-wth Figure 



Figured lumber may be sawed from any tree trunk whose growth 

 rings are easily visible. That figure is so common that it is taken 

 for granted, and only where it is developed with considerable strength 

 is it commercialized. Ash and chestnut have been mentioned, and it 

 is strong in all oaks and in most of the firs and yellow pines. On 

 the other hand there are many trees with rings weak and not clearly 

 defined. 



Figures in lumber, due to the tree's rings, are of three general 

 patterns, depending upou the way they appear on the sawed surface. 



A log sawed square ofl! exposes the rings as concentric circles, from 



GROWTH RING FIG'DRE SLAB CUT . 



This is the most common figure developed In sawing lumber, and Is strongest 

 in woods which have broad and distinct rings of growth. 



center to the bark. This figure is usually distinct, if the surface is 

 polished, but the woodworker makes Uttle use of it. Transverse wood 

 sections are not adapted to common purposes. 



A second figure is exposed when a slab is taken off the side of a log. 

 Edges of the rings are cut off and displayed. If the log has crooks 

 or large knots, the saw will cut diagonally across many of the rings, 

 and there wiU appear on the surface of the lumber sections of the 

 rings in the forms of circles, elipses and parabolas which sometimes 

 form attractive figures, though if too often repeated they become 

 monotonous. 



A tliird growth-ring figure is developed when the saw cuts the log 



EXAMPLES OF GROWTH-RING FIGURES 

 Pieces of molding which display the plainest pattern of figure developed by cutting across the rings of annual growth in oak. 



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