CLASSIFICATION OF WOODS BY STRUCTURAL CHARACTERS 243 



tification. Purposely or through ignor- 

 ance, importers appear constantly to be 

 endeavoring to palm off upon their cus- 

 tomers substitute woods, sometimes in- 

 ferior, whose superficial appearance is 

 close enough to deceive the uninitiated. 

 The real mahogany, Swietenia mahog- 

 ani is now becoming scarce, and at least 

 a score of different woods from Central 

 and South America, India. Africa, and 

 the Philippine Islands, are being sold 

 as the "only genuine mahogany." The 

 Australian eucalyptus and a number of 

 other woods are being so skillfully 

 stained to imitate ebony that no one ex- 

 cept an expert can distinguish the coun- 

 terfeit. 



Dr. Schlich once remarked that as 

 the timber supply declined in the north- 

 ern hemisphere another suitable source 

 of supply must be looked for in the 

 southern hemisphere. The demand for 

 different woods and the growing scarce- 

 ity of the most useful kinds in this 

 country forces us to go to the tropical 

 countries of the southern hemisphere 

 for millions of feet annually. The for- 

 eign woods now in general use are too 

 numerous to be distinguished by super- 

 ficial characters. We must look to min- 

 ute structural characters as a means of 

 tracing down woods with which we are 

 not familiar. For this, recourse must be 

 had to the microscope. The result of 

 such investigations are far reaching in 

 usefulness, including the needs of the 

 forester, lumberman, and timber mer- 

 chant, and even of the pharmacist. There 

 are numerous medicinal properties de- 

 rived from different woods, and it is 

 very important in their preparation that 

 the right kind of wood be used. There 

 are certain woods, for instance, that re- 

 semble quassia in external appearances. 

 In order to detect the numerous at- 

 tempted uses of these as substitutes or 

 adulterants of .genuine quassia, it is nec- 

 essary to know the microscopical char- 

 acters of quassia to distinguish the real 

 from the spurious wood. 



Work of this character is primarily 

 technical, but it does not aim to replace 



entirely nor to underrate the old rule 

 of thumb method. Attention is drawn 

 only to the necessity for more scientific 

 investigations of woods and the compil- 

 ation of existing expert knowledge as 

 a means of meeting the needs of tech- 

 nical institutions and of private per- 

 sons possessed of the training and 

 equipment to make use of such help. It 

 is not implied by this that the more ob- 

 vious characters of woods seen in the 

 block should not form part of the natu- 

 ral system so far as they can be made 

 to serve. Such characters of wood, as 

 color, weight, hardness, and odor, 

 often help in making determinations. So 

 also color solutions, obtained by boiling 

 the wood in water, acid, alkali, iron 

 salts, or glycerine, yield very valuable 

 and interesting data. Even burning 

 tests are often helpful in discriminating 

 between woods. For example, the eu- 

 calypt Jarrah always burns to a black 

 ash, while Karri, another species, burns 

 to a white ash. The importance of such 

 characteristics can not be too greatly 

 emphasized. 



Since systematic botanists generally 

 have no special concern in the identifica- 

 tion of woods, it is a task that naturally 

 devolves upon the foresters who are 

 professionally interested in the uses of 

 this and other forest products. The 

 field is so large and all-absorbing as to 

 require specialization apart entirely 

 from other branches of technical fores- 

 try. It requires a specialist trained not 

 only as a lignologist, but also as a botan- 

 ist. Moreover work of this character 

 requires a most sedulous investigator 

 with one aim, the good of the work. 



Such a work as this has fitly become, 

 with other dendrological investigations, 

 a most important economic study in the 

 Forest Service of the United States De- 

 partment of Agriculture. The results, 

 which are being very rapidly put into 

 shape for publication, are practical aids 

 to practical manufacturers and users of 

 woods, as well as to other students of 

 trees and other products. 



