52 SCHOOL AGRICULTURE 



3. Determining Age of Trees. Cut cross sections of branches, as 

 large as can be conveniently obtained and give each pupil a section. 

 Count the rings of growth in the cross sections and note the age of 

 the branches. Make drawings of the sections, showing bark, rings 

 of growth, and pith rays. 



LESSON XV. 

 TREE SOCIETIES THE FOREST. 



Forest Conditions. Trees grow together in societies and 

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

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

 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 foot-hold, resulting in the for- 

 mation of forest crowns, forest trunk masses, and forest floors. 

 The ideal forest crown has all its tree tops touching each 

 other, so as to completely shade the ground without over 

 crowding 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-mould 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 every 

 hundred tons of coal mined, two tons of mining timber are 

 needed. For our means of transportation we rely mainly on 

 wood. Millions of telephone poles are needed to keep up our 

 communications. The forest furnishes the wood for all the 

 implements of the farm, and for all the vehicles of transpor- 

 tation there. Lumber is not the only product of the forest. 

 There is the turpentine of the pine, the paper pulp of the 

 spruce and poplar, the tan bark of the oak and hemlock, the 

 sugar and syrup of the maple, and the various distilled prod- 

 ucts from many other species. The alarming fact of this im- 

 mense supply, is that we are using wood three times faster 

 than it is growing. 



Forest Influences. In addition to serving as a great source 



