OUR FORESTS 21 
tapped in February or March by boring small holes in the sapwood. 
A spout is inserted in each hole and a bucket hung beneath it to 
catch the sap which drips out. The collected sap is carried to the 
sugar house, where it is boiled down to the proper consistency for 
sirup or sugar. Most of the maple products 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 products 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 gallon. 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. 
ForRESTS AND THE WATER SUPPLY 
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- 
cepted by the leaf litter. It sinks gradually into the soft absorbent 
soll 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 area exercises a major influence on stream 
flow and an additional quarter a moderate influence. The area 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 have 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 offers oppor- 
tunity for pleasure and recreation for both young and old. It is, of 
course, an ideal camping place; it furnishes playgrounds and shaded 
