OUR FORESTS 21 



tapped in February or Marcli by boring small holes in the sapwood. 

 A spout is inserted in each hole and a bucket hung beneath it to 

 caten the sap which drips out. The collected sap is carried to the 

 sugar house, where it is boiled down to the proper consisteney for 

 sirup or sugar. Most of the maple producís come from the North- 

 eastern and Northern States, but a few other States also produce 

 them in commercial quantities. 



There are also numerous other forest produets of more or less im- 

 portance. The bark blisters of the balsam fir produce a resin which 

 when refined sells for as much as $40 a gallón. In spite of all the 

 work and skill of the chemists, wood and bark remain the chief 

 sources of tannins, and dyes from various trees, such as black oak and 

 Osage-orange, are still to be found in trade channels. Many kinds 

 of edible nuts and fruits, crude drugs, and Christmas greens also 

 come from our forests. 



FORESTS AND THE WATER SüPPLY 



Forests give invaluable service to man through the protection of 

 watersheds and the regulation of stream flow. The thick crowns of 

 the forest trees, which sometimes almost entirely shut the sunlight 

 from the forest floor, also break the fall of the rain. Down on the 

 forest floor the water from rain or melting snow is likewise inter- 

 ceptad by the leaf litter. It sinks gradually into the soft absorbent 

 soil beneath, and some of it eventually finds its way underground to 

 the springs and streams (fig. 13). This checking of surface waters 

 tends to make stream flow regular and continuous throughout the 

 year. Where watersheds are not protected, rains fall on bare soil. 

 and the water rushes down the slopes, with the result that streams 

 rise quickly to flood height and as quickly dwindle away. 



Adequate watershed protection insures an abundance of water for 

 use in homes, for irrigation of cultivated lands, and for river naviga- 

 tion. It helps to make constant the power which turns the wheels 

 of many a factory and furnishes electric current for numberless uses. 

 It keeps the rains from washing away huge quantities of rich soil, 

 leaving hillsides bare and unproductive and choking river beds and 

 bottoms with heavy deposits of mud. 



One-half of our forest área exercises a major influence on stream 

 flow and an additional quarter a modérate influence. The área of 

 major influence, however, feeds streams that flow through nearly 

 every other part of the country. Therefore, practically our entire 

 population directly or indirectly benefits from forest protected waters. 



Other Uses of the Forest 



Forests ha ve still other protective uses. They help to prevent land- 

 slides and snowslides; they protect homes, fields, and orchards from 

 cold and destructive winds; and in some parts of our country they 

 give permanent form to sand dunes, which otherwise would be con- 

 stantly shifting from place to place, sometimes burying fences, roads, 

 and railways. 



Besides serving us in these various ways the forest oífers oppor- 

 tunity for pleasure and recreation for both young and oíd. It is, of 

 course, an ideal camping place ; it furnishes playgrounds and shaded 



