FOREST TREES AND FOREST SCENERY 
of the forest. The character of the 
climate, the nature of the soil, the de- 
gree of moisture in the soil and in the 
atmosphere, the amount and intensity 
of the sunlight —in short, the various 
elements and natural forces that con- 
stitute the environment of a tree —are 
the all-important conditions of its life. 
On these it depends, and according to 
its own peculiar nature and its special 
needs, selects its natural home. 
Yet the manner in which this selec- 
tion is accomplished, though simple in 
theory, is complicated by many circum- 
stances. Frost, fire, insects, and floods, 
by destroying the trees or their seeds, 
may retard the progress of the species. 
The wind may be unfavorable. The 
seeds hang upon the trees ready and 
ripe for germination, but a breeze comes 
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