l8 99- 



AMERICAN FORESTRY ASSOCIATION. 



sS 7 



aging new growth, than to allow them to 

 go to maturity and decay untouched. 

 The guardians of the forest preserves 

 should he required to gather seeds of trees 

 and plants and sow them wherever they 

 can be induced to grow. They should 

 keep the young groves properly thinned 

 out and have authority to sell saw-logs and 

 firewood wherever the trees can be judi- 

 ciously spared. 



One of the important, though little con- 

 sidered, uses of the forest to the irrigator 

 is the conversion of organic vegetable mold 

 into nitrogenous plant- food. This is going 

 on through the agency of the ever-present 

 bacteria which re-convert the organic waste 

 of the world into innocuous and useful 

 mineral matter. Water filtering through 

 the soil is constantly bearing these mineral 

 nitrates into the streams and thence out 

 upon the lands. Streams from treeless 

 mountains lack these nitrogenous elements 

 to a great degree, and the water has less 

 fertility and is less valuable for irrigation. 



The effect of the destruction of forests 

 in mountainous regions is eloquently de- 

 scribed by the eminent French political 

 economist, Blanqui, in a memoir read be- 

 fore the Academy of Moral and Political 

 Science of France, in 1843. He says, 

 referring to the Alps of southern France : 



" Signs of unparalleled destruction are 

 visible in all the mountain zone, and the 

 solitudes of those districts are assuming 

 an indescribable character of sterility and 

 desolation. The gradual destruction of 

 the woods has, in a thousand localities, 

 annihilated at once the springs and the 

 fuel. The abuse of the right of pasturage 

 and the felling of the woods have stripped 

 the soil of all its grass and all its trees, 

 and the scorching- sun bakes it to the con- 

 sistency of porphyry. When moistened 

 by the rain, as it has neither support nor 

 cohesion, it rolls down to the valleys, 

 sometimes in floods resembling black, 

 yellow, or reddish lava, sometimes in 

 streams of pebbles, and even huge blocks 

 of stone, which pour down with a fright- 

 ful roar, and in their swift course exhibit 

 the most convulsive movements. No 

 tongue can give an adequate description 

 of their devastations in one of those sud- 



den floods which resemble in almost none 

 of their phenomena the action of ordinary 

 river water. They are now no longer 

 overflowing brooks, but real seas, tumbling 

 down in cataracts and rolling before them 

 blocks of stone, which are hurled forward 

 by the shock of waves like balls shot out 

 by the explosion of gunpowder. A furi- 

 ous wind precedes the rushing water and 

 announces its approach. Then comes a 

 violent eruption, followed by a flow of 

 muddy waves, and after a few r hours all 

 returns to the dreary silence which at 

 periods of rest marks these abodes of 

 desolation." 



After years of agitation and discussion, 

 the work of restoring the woods, and of 

 controlling the floods and destructive ero- 

 sion of the torrents, was undertaken by 

 the French Government, at enormous 

 cost, but with gratifying results, wherever 

 carried out. The improvements consisted : 

 (1) of the systematic planting of trees, 

 grass and underbrush near the source of 

 the streams to prevent the sudden and 

 rapid collection of large quantities of rain 

 and melted snow water. (2) The protec- 

 tion of the shores of the streams from 

 undermining, and their beds from erosion, 

 by the erection of small dams of masonry, 

 loose rock, and brush, to diminish the 

 grade and decrease the power of the water, 

 to raise and widen the bed, and retain and 

 store detritus. Many of these structures 

 were made of green branches that were 

 induced to take root and grow. (3) The 

 terracing of the mountain slopes in a way to 

 retard the run-off and guide the water into 

 channels of light grade, where it could be 

 conducted to the main streams without 

 washing the soil. On one smal 1 watershed 

 of less than 1,000 acres the Government 

 expended $125,000, but the benefits re- 

 sulting immediately after completion were 

 estimated at more than double that sum. 



The Austrian and Swiss Governments 

 have done a great deal of this work to re- 

 store the mountain watersheds to their 

 original condition before the Eorests were 

 destroyed, and great numbers of masonry 

 dams have been erected to an extreme 

 height, in one case in the gorge of Ferrina, 

 Australian Tyrol, of 116 feet. These are 



