The North American Forest 21 



there are a few general rules of practical impor- 

 tance to the forester. A tree standing in the open, 

 where the light strikes its crown from all sides, 

 forms a round, symmetrical top, with the lowest 

 branches not very far above the ground. Or if it 

 is of the kind that has a pyramidal growth, like the 

 spruces and most other coniferous trees, it may be 

 clothed with living branches to the very earth. If 

 the same kind of tree should grow in a place where 

 it gets full sunlight from some directions, while 

 other sides are shaded, the branches will all, or 

 nearly all, grow towards the light, thus forming 

 .asymmetrical crowns. Now suppose that a tree of 

 the same species should find itself standing in a 

 dense clump of trees, where the light cannot reach 

 it from any side. Then its only salvation is to 

 reach the light which comes from above. Conse- 

 quently it sends out few and small lateral branches, 

 but puts all its energy into height growth, until it 

 has grown above the shade cast by the surround- 

 ing trees. This done, it begins to spread its leafy 

 branches in all directions, to absorb as much of the 

 loved sunlight as possible. Where a number of 

 trees grow closely together, so as to mutually hin- 

 der the light from reaching their leaves, a race for 

 the sun ensues between them, in which those are 

 victorious which by reason of their more ener- 

 getic height growth first show their tops above 

 the others. Then these begin to spread their 

 side limbs, thereby throwing their rivals into 

 ever denser shade, and the latter cease to grow 



