X. OUR FORESTS; THEIR USES AND THE NECESSITY 

 FOR THEIR PROTECTION 



Problem XIX. Sdiiie lo.scs of stems {optional). (Labor fttoTjj 

 JIniiual, Proh. AT,!'.) 

 (a) Special product from stei)is. 

 il>) Some woods aiul tJicir j-al/ie. 

 (c) Pi eld icork in forcstrij. 



The Economic Value of Trees. Protection and Regulation of 

 Water Supply. — Trees form a protective covering for the earth's 

 surface. They prevent soil from being washed away, and they hold 

 moisture in the ground. Without trees many of our rivers might 

 go dry in summer, while in the rainy season sudden floods would 

 result. The devastation of 

 immense areas in China and 

 considerable damage bj' 

 floods in parts of Switzer- 

 land, France, and in Penn- 

 sylvania has resulted where 

 the forest covering has been 

 removed. No one who has 

 tramped through our Adi- 

 rondack forest can escape 

 noticing the differences in 

 the condition of streams 

 which flow through areas 

 covered with forest and those from arouufi which trees have 

 been cut. The latter streams often dry up entirely in hot 

 weather, while the forest-shaded stream has a ne\-er failing 

 supply of crystal water. 



The city of New York owes much of its importance to its posi- 

 tion at the mouth of a great river with a harbor large enough to 

 float the navies of the world. This river is supplied with water 



133 



Working i<i |in\rut erosion aftrr ihv rcaiu\;il 

 of the forest in the French alps. 



