I.— ECOLOGICAL INVESTIGATIONS UPON THE 



GERMINATION AND EARLY GROWTH 



OF FOREST TREES 



BY RICHARD H. BOERKER 



CONTENTS 



Page 



Prefatory Note I 



Preliminary Considerations 7 



Historical 7 



Classification and Resume of Habitat Factors II 



The Germination Process 151- 



Method of Attacking Problem at Hand 19 



Methods and Apparatus Used 21 



The Control of Habitat Factors 24^ 



Notes on Damping-off 32 



The Effect of Habitat Factors upon Germination 34 



The Effect of Habitat Factors upon Stem and Root Development .... 64 ^ 

 The Relation of Size and Weight of Seed to Germination Per Cent. 



and Early Development 70 L 



Summary of Conclusions 82 



Bibliography 88 



PREFATORY NOTE 



Almost every national industry makes provision for investiga- 

 tive work. Millions of dollars are spent annually to develop both 

 human and mechanical efficiency. It is immaterial whether the 

 investigations are for the purpose of utilizing certain products 

 hitherto considered waste, or to make workmen more efficient, 

 or to employ the latest processes and inventions to better survive 

 in the competitive struggle — the results of this class of work are 



