96 THE HUMAN SIDE OF TREES 



on the mountains, the trees grow small and com- 

 pact hugging the ground almost like bushes. This 

 tends to make them crooked and deformed and a 

 little unlovely, but they have an important place 

 in the economy of the woods. The scrubby-looking 

 trees far up on the timber line help to bind down 

 the earth and shade the moss of those altitudes. 

 The earth and the moss soak up the rain as its falls 

 and thus prevent the water from tearing madly 

 down the slope in a devastating flood to be later 

 succeeded by a more injurious drought. The aris- 

 tocratic trees of the valley owe their lives and pros- 

 perity to their stunted brethren high above them. 



The life of the ordinary tree of the forest is 

 marked by a continual use of shrewd and ingenious 

 business methods. Every one knows how the trees 

 protect themselves from the winter cold by an extra 

 coat of bark and moss on the side of the prevailing 

 winds (usually the north). Conversely, the long- 

 est and largest limbs are most often to be found on 

 the southern exposure, away from the dangers of 

 the icy blast. 



The trees are the best mechanical engineers in 

 the world. Each individual is built so that the 

 various loads and stresses of its body are taken care 

 of to best advantage. The main stems of tapering 

 trees, like the California pines, in structural de- 



