Germination of Forest Trees 



43 



a higher per cent, in the medium shade, and six a higher per 

 •cent. in the dense shade than in the other cultures. 



On page 42 are given the germination curves of Pseudotsuga 

 iaxifolia (Wash.), and Picea sitkensis. Both sets of curves show 

 that germination begins sooner, the curve rises more rapidly and 

 the final germination per cent, is higher in the case of seeds 

 germinated in the shade as compared to light. 



TABLE IV 



The Effect of Soil Moisture on Germination 



Eastern Species 



Dry Soil 



Species 



Pinus strobus 



Pinus divaricala 



Pinus divaricala (F. S.) . 



Pinus resinosa 



Pinus palustris 



Pinus laeda 



Abies balsamea 



Catalpa speciosa 



Catalpa speciosa (Neb.) . 



Quercus rubra 



Robinia pseudacacia . . . . 



Betula papyrifera 



Acer rubritm 



24 



10 30 



10. 

 7-5 



2-5 



15-0 



1 3.0 



Medium Wet Soil 



30 

 14 

 22 

 24 

 36 



24 



34 

 50 

 18 



40 

 50 



8.0 



53-5 

 4.0 



49.0 

 6.0 



12.0 



4.0 



32.0 



12.0 





10.7 



54-5 

 39-S 

 30.5 

 10.5 

 19.0 

 11. o 



1.0 

 91.0 

 28.0 

 28.8 



1.0 

 17.0 



Tables IV, V, and VI consider the same species as the three 

 preceding tables from the standpoint of soil moisture instead of 

 light. 



In Table IV in practically every case where a comparison is 

 possible germination started in the wet soil culture, and was de- 

 layed as the soil moisture content was reduced. Also the germi- 

 nation period is shortened with decrease in soil moisture. The 

 final germination per cent, in every case but one was highest in 

 the wet soil. Finns resinosa showed the highest per cent, in the 

 medium wet soil. 



This table separates the species into classes based upon their 

 ability to germinate in dry soil, medium wet soil, or wet soil. 



