Germination of Forest Trees 



37 



II species show a longer germination period in the shade than 

 in the light. The other three species did not germinate suffi- 

 ciently to make a conclusion possible. 



TABLE I 



The Effect of Light on Germination 



Eastern Species 



Species 



Medii 



1 Shade 



Began, 

 Days 



Period, 

 Days 



Final, 

 Per 

 Cent 



Dense Shade 



Final, 

 Per 

 Cent 



Pinus strobus 



Pinus divaricate 



Pinus divaricata (F. S.) 



Pinus resinosa 



Pinus palustris 



Pinus taeda 



Abies balsamea 



Calalpa speciosa 



Catalpa speciosa (Neb.) 



Quercus rubra 



Robinia pseudacacia . . . 



Betula papyrifera 



Acer rubrum 



Gleditschia triacanthos . 



16 

 10 

 14 

 16 

 32 

 34 

 18 



o 

 14 

 30 



6 

 34 

 16 



6 



54 

 26 

 26 



24 

 82 



6 

 38 





 20 

 18 

 18 



1 

 34 



n-5 

 63.5 

 37-0 

 50.0 

 12.0 

 33-0 

 10. o 



0.0 

 92.0 

 12.0 

 29.0 



2.0 

 15.0 



2.0 



8.0 

 73-5 

 46.5 

 74-5 



5-5 

 330 



8.0 



1.0 

 88.0 

 12.0 



33-5 

 1.0 



16.0 

 2.0 



Three species had a higher germination per cent, in the open 

 light than in either of the shade cultures. Four showed the 

 highest per cent, in the medium light and six in the dense shade. 

 The greatest difference was shown in the case of Pinus resinosa 

 whose germination per cent, was almost two and one half times 

 greater in the dense shade than in the open light culture. 



The germination curves of Pinus resinosa and of Pinus divari- 

 cata are given on page 38. These are representative of the 

 effect that light has upon germination. These curves show a 

 greater germination per cent, in the dense shade culture, a more 

 rapid rise of the germination curve in the dense shade and that 

 germination begins sooner in the shade than it does in the light. 



