PREFACE 



Ever increasing numbers of people are becoming interested 

 in the trees and forests of North America. Regional manuals 

 of our native trees are available for the different sections of 

 the United States and Canada, but no simple yet complete 

 up-to-date field manual for the entire area has been available. 



This manual covers the trees of North America with the 

 exception of Mexico and the tropical species found in the southern 

 fringe of the United States. Care has been taken to include all 

 tree species native to this area (except for the 162 species of 

 hawthorn and 20 usually shrubby willows which, for the most 

 part, can only be distinguished by specialists), as well as natural- 

 ized or commonly planted exotic species. 



In all, 135 genera containing 568 species are treated. Draw- 

 ings showing descriptive characters, distribution maps, and 

 concise descriptions of botanical and silvical characters have 

 been included for 232 species of trees which are either of impor- 

 tance or general interest, while an additional 336 less impor- 

 tant species are either briefly described or included in the 

 complete keys. 



North American Trees has been designed to meet the needs 

 of an interested nontechnical public, as well as those of students 

 and scientists. The terminology has been kept as simple as 

 possible without sacrificing scientific accuracy. Basic informa- 

 tion on characters and techniques used in identifying trees 

 appears in the introduction, and a comprehensive glossary 

 defines necessary technical terms that might not be generally 

 understood. It is believed that anyone interested in knowing 

 how to identify the native trees will find this manual under- 

 standable and easily used. 



The nomenclature of woody plants follows the 1944 revision 

 of the United States Forest Service check list. Inasmuch as this 

 revision follows the International Rules of botanical nomen- 

 clature, rather than the American Rules followed by earlier 

 authors, there have been numerous changes in tree names from 

 earlier manuals. 



There are 1 60 full page plates containing drawings of 232 



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