Germination of Forest Trees HG 
the per cent. in favor of the large seeds. In converting grams 
to pounds it was assumed that 453.6 grams equals one pound. 
The germination period for Pinus ponderosa was 120 days and 
for Pseudotsuga taxifolia 100 days. 
_ From these tables it will be seen that in every variety of Pinus 
ponderosa the final germination per cent. is in favor of the large 
seeds. In the case of Pseudotsuga taxtfolia every variety except 
one shows a final per cent. in favor of the large seeds. 
It is well known that there are definite climatic differences 
between the Rocky Mountains and the Pacific coast. The most 
conspicuous proof of this is in the flora of these regions. In 
general the Pacific coast is inhabited by relatively mesophilous 
vegetation, especially near the coast, while the vegetation of the 
Rocky Mountains is more xerophilous in nature. Again, the 
Rockies themselves show marked differences in this very respect 
in travelling from south to north and from east to west. 
Probably the best way of studying the effect of great climatic 
variations upon vegetation is to use polydemic species such as we 
are considering here. Pinus ponderosa and Pseudotsuga taxi- 
folia are conspicuous examples of this class of species. It is 
well known that both these species reach a better development on 
the Pacific coast than in the Rocky Mountains. It is likewise 
well known that they reach a far better development in the 
northern Rockies than in the southern. As a proof of this we 
have but to go to volume tables of these species in the Woods- 
man’s Handbook by Graves and Ziegler. In the case of Pinus 
ponderosa three tables are given, one for the Black Hills, one for 
Arizona, and one for California and Montana. In studying 
these tables it will be seen that the maximum heights and 
maximum diameters and the average and maximum heights for 
a given diameter increase steadily in going from the Black Hills 
to California. In the case of the Douglas fir the same thing is 
true in considering the volume table for Idaho and Wyoming 
and that for Washington and Oregon. In the order of their 
favorability for tree growth, as manifested by these species these 
regions arrange themselves in the following order, the least favor- 
able being given first: 
