FARM FORESTRY 243 



of a young tree, and of an old tree whose heart has not 

 decayed, is the pith, soft, thin- walled cells in which food is 

 stored. The pith extends in radiating rays out to the bark. 

 In a cross section of a tree we can see pith, pith rays, rings 

 of growth, heart wood, sap wood, and bark. 



TREE SOCIETIES THE FOREST 



Forest conditions. Trees grow together in societies and 

 make what are known as forest conditions. The forest has a 

 story quite different from that of a single tree. Here the 

 trees struggle with one another for the best position, like 

 people in a crowd jostling one another to get sight of some 

 common attraction before them. In the forests trees struggle 

 with each other for light, food, and foothold, resulting in 

 the formation of forest crowns, forest trunk masses, and for- 

 est floors. The ideal forest crown has all its tree tops touch- 

 ing each other, so as to completely shade the ground without 

 overcrowding any single tree; the wood mass has clear, 

 straight boles and the maximum number to the acre ; and the 

 forest floor is rich in leaf -mold and free from grass and fire- 

 traps. 



The wood supply. The prime importance of the forest to 

 mankind is its wood supply. Outside of food products no 

 material is so universally used as wood. Indeed, civilization 

 is inconceivable without an abundance of timber. Wood sur- 

 rounds us on every hand as a convenience or a necessity. We 

 require wood in the construction of our homes. It serves 

 to ornament them, to furnish them, and to heat them. For 



