Germination of Forest Trees 



39 



TABLE II 



The Effect of Light on Germination 



Rocky Mountain Species 



Species 



Open Light 



a 



Pinas ponderosa S.D. 



Pinus ponderosa Harney 



Pinus ponderosa N.M. 



Psendolsuga taxifolia N.M. 



Pseudotsuga taxifolia Colo. 



Abies concolor Colo. 



Pinus contorta Colo. 



Pinus ponderosa Mon. 



Pseudotsuga taxifolia Mon. 



Pseudotsuga taxifolia Idaho 



Pinus ponderosa Idaho 



Abies grandis Idaho 



Abies lasiocarpa j Idaho 



Pinus mon ti cola I Idaho 



5 



10 



14 

 14 



12 



12 



24 



14 

 18 



14 

 18 

 36 

 36 

 30 



C >, 



EL, 



32 



14 

 40 

 26 

 42 



So 

 80 

 12 



34 

 30 

 52 

 36 

 30 



24 ! 50 



Medium Shade 



58.0 



52.0 



56.0 

 63.O 

 91.0 

 38.0 

 22.0 

 10. 

 20.5 

 20.5 

 42.0 

 4-0 



6.0 

 22.5 







10 



8 

 12 

 10 

 12 

 18 

 16 

 18 

 12 

 16 



24 

 22 

 26 

 16 



22 

 26 

 32 

 12 

 36 

 56 

 70 

 54 

 32 

 64 

 66 

 62 

 SO 



. a 



Dense Shade 



c 

 -1 

 be ^ 



D nl 



.0 

 >.0 

 .0 



58 20.0 



56. 

 58. 

 82, 



69, 



73 



54. 



1 

 15 

 IS 

 49 

 52 

 16 



7 



5| 10 

 o 8 



10 



10 



8 



14 

 14 

 10 



5 12 

 o 10 



T3 tn 



PL, 



14 



22 

 22 



14 



34 

 26 

 12 

 16 

 36 

 60 

 72 

 8 



44 

 64 

 82 

 60 

 28 

 60 



V 



PL, 



58.5 

 63.0 

 79.0 

 65.0 

 82.0 

 56.0 



3-5 

 9.0 

 35-0 

 50.0 

 43-0 

 10. o 

 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 



