Germination of Forest Trees 



5i 



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

 tion per cent, in the loam are Quercns rubra and Acer rubrnm. 

 Nine species reached their highest germination per cents, in the 

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

 ously: Pinus divaricate, 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 



Pinus ponderosa 



Pinus ponderosa. . . ... 



Pseudotsuga taxifolia 

 Pseudotsuga taxifolia . 



Abies concolor 



Pinus contorta 



Pinus ponderosa 



Pseudotsuga taxifolia . 

 Pseudotsuga taxifolia . 



Pinus ponderosa 



AbieS grandis 



Abies lasiocarpa 



Pinus monticola 



3U 



44-0 

 130 

 57-5 

 63-5 

 80.0 

 34-0 



40.5 

 4.0 



44-5 



43 -o 



71.0 



3-o 



o 



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 



