Germination of Forest Trees 



39 



TABLE II 



The Effect of Light on Germination 



Rocky Mountain Species 



Species 



Pinus ponderosa 



Pinus ponderosa 



Pinus ponderosa 



Pseudolsuga taxifolia . 

 Pseudotsuga taxifolia . 



Abies concolor 



Pinus contorta 



Pinus ponderosa 



Pseudotsuga taxifolia. 

 Pseudolsuga taxifolia . 



Pinus ponderosa 



A bies grandis 



A bies lasiocarpa 



Pinus monticola 



S.D. 

 Harney 

 N.M. 

 N.M. 

 Colo. 

 Colo. 

 Colo. 

 Mon. 

 Mon. 

 Idaho 

 Idaho 

 Idaho 

 Idaho 

 Idaho 



Open Light 



a« 





32 



14 



40 



26 



42 i 



50 



80 



12 



34 

 30 I 

 52 

 36 I 

 30 

 50 



Medium Shade 







Dense Shade 



58.0 

 52.0 

 56.0 

 63.0 

 91.0 

 38.0 

 22.0 

 10. 

 20.5 

 20.5 

 42.0 



4.0 



6.0 

 22.5 



12 



10 



12 



18 

 16 

 18 



12 

 16 

 24 

 22 

 26 

 16 



26 

 32 

 12 

 36 

 56 

 70 

 54 

 32 

 64 

 66 

 62 

 50 

 58 



S6.5 

 58.0 

 82.0 



69.0 



J 73-5 



54-0 



7-5 

 15.0 

 15-5 

 49.0 

 52.0 

 16.0 



7.0 

 20.0 



10 

 10 

 8 

 14 

 14 

 10 

 12 

 10 



14 

 22 

 22 



14 



34 

 26 

 12 

 16 

 36 

 60 

 72 

 8 



44 

 64 

 82 

 60 

 28 

 60 



58.5 



63.0 



79.0 



65.0 



82.0 



'56.0 



3-5 



9.0 



35-0 



5°.o 



43-0 



10. 



6.0 



36.5 



In Table II 12 species out of a total of 14 germinated first in 

 the dense shade, the other two germinated simultaneously in the 

 dense shade and open light. The number of days difference 

 between the two cultures varied from 2 to 22 days. Pinus pon- 

 derosa (Harney) germinated 6 days earlier in the dense shade 

 than in the open light, Pinus ponderosa (N. M.) 4 days, Pseu- 

 dotsuga taxifolia (N. M.) 2 days, Pseudotsuga taxifolia (Colo.) 

 4 days, Abies concolor 10 days, Pinus ponderosa (Mon.) 8 days, 

 Pseudotsuga taxifolia (Mon.) 2 days, Pseudotsuga taxifolia 

 (Idaho) 8 days, Pinus ponderosa (Idaho) 22 days, Abies grandis 

 14 days, Abies lasiocarpa 8 days, and Pinus monticola 10 days. 

 The medium shade cultures in most cases represent a condition 

 intermediate between the open light and dense shade. 



In 10 species out of 14 the germination period was longer in 

 the shade than in the light. In 6 species the germination per cent, 

 was higher in the dense shade than in either of the other two cul- 

 tures and in 12 cases out of 14 the highest per cent, was in either 

 of the two shade cultures as against the light culture. In other 



