PREFACE. 



The following is a brief untechnical presentation of gen- 

 eral features characterizing economically important species of 

 wood. It is the result of notes originally brought together 

 from many already existing sources and later augmented, and 

 verified so far as possible for the present use, by personal 

 observation. The work of preparation has not been as simple 

 as the result would indicate, and although great care has been 

 taken to check each fact, errors do no doubt exist, although 

 it is not believed that there are important ones. 



Engineers while writing upon woods have, save excep- 

 tionally, emphasized strength beyond most other properties. 

 Other works for expert foresters or botanists are of necessity 

 too special, voluminous, fragmental, or technical for the casual 

 student. Some popular books on trees, as distinct from 

 woods, are available. The present form is distinct from these 

 and is intended for those who are not foresters or botanists, 

 but who use woods or desire knowledge of their distinguishing 

 properties. Allusions to trees, historical and other references, 

 aside from those directly regarding woods, are made for 

 completeness and in order to mark, distinguish, or separate 

 the species. 



Acknowledgments are particularly due to the publications 

 of the U. S. Division of Forestry, to Prof Sargent's studies as 

 set forth in Vol. IX of the Tenth U. S. Census, to Dr. B. E. 

 Fernow, to Mr. Raphael G. Zon for suggestions and for tech- 

 nical revision, to the Nortliwestern Lumberman and other trade 



