Germination of Forest Trees 



5' 



The two species that stand out as having the greatest germina- 

 tion per cent, in the loam are Oucrcus rubra and Acer rubrum. 

 Nine species reached their highest germination per cents, in the 

 sand and in this group the following stand out most conspicu- 

 ously : Pinus divaricata. Pinus resinosa, Pinus palustris, Pinus 

 taeda, and Robinia pseudacacia. Being species of sandy habitats 

 it is quite easy to see why they should germinate better in the 

 sand. In the gravel, which is a poor moisture retainer, it is in- 

 teresting to compare such a drought enduring species like Pinus 

 divaricata and such a moisture-loving species like Pinus taeda. 



On page 50 are given the curves for Pinus divaricata and Pinus 

 resinosa. 



TABLE VIII 



The Effect of Soil Texture on Germination 



Rocky Mountain Species 



Species 



Pinus ponderosa S.D. 



Pinus ponderosa Harney 



Pinus ponderosa N.M. 



Pseudotsuga iaxifolia ... . N.M. 



Pseudotsuga Iaxifolia Colo. 



Abies concolor Colo. 



Colo. 



Mon. 



Mon. 



Idaho 



Idaho 



Pinus conlorta 



Pinus ponderosa 



Pseudotsuga Iaxifolia . . . 

 Pseudotsuga iaxifolia . . . 



Pinus ponderosa 



Abies grandis j Idaho 



Abies lasiocarpa | Idaho 



Pinus monticola : Idaho 



10 

 14 

 14 

 12 

 12 

 24 

 14 

 18 



14 

 18 

 36 

 36 

 30 

 24 



Sand 



32 



14 

 40 

 26 



42 

 SO 

 80 

 12 

 34 

 30 

 52 

 36 

 30 

 SO 



58.0; 

 52. 



56.0I 



63.0 

 91.0 



380 



22.0 

 10. 

 20.5 



20.5J 



43-0 

 4-0 

 6.0 



22. 5 



14 



20 

 26 

 26 

 22 

 38 

 66 

 66 

 48 

 44 

 54 

 52 

 6 

 o 

 50 



57-5 

 4S-o 

 7i-5 

 70-5 

 83-5 

 51-0 

 19-5 

 11. 

 43-0 

 11. 

 59-o 



2.0 





 H-S 



2 >> 



8 j 38 



14 1 8 



12 12 



10 14 



10 44 



20 , 48 



16 j 70 



18 ! 1 



44.0 

 130 

 57.5 

 635 



80.0 



34.0 



40.5 



4.0 



44-5 

 43-0 

 71.0 

 3-0 

 o 

 13-5 



Table VIII gives the results for the Rocky Mountain species. 

 Out of 13 species, 8 germinated first in sand or in gravel, only 

 one germinated first in loam, and four germinated simultaneously 

 in loam and in sand or gravel. Eight species show a longer 

 period of germination in sand or gravel than in loam, and 5 

 species show the same length of period in either sand or gravel 

 and in loam. Six species show a higher germination per cent, in 



