vi PREFACE 



fessor of Forestry at the' Michigan Agricultural College, who 

 read Chapters 1-18, and to my associates on the Faculty of 

 the Department of Forestry, of The Pennsylvania State Col- 

 lege; C. R. Anderson, who made many valuable suggestions; 

 R. R. Chaflfee, who read Chapters 11-20; W. G. Edwards, 

 who helped in the preparation of the index, and G. R. Green, 

 who read and corrected the entire manuscript. 



J. A. Ferguson. 



