126 Conservation Reader 



winter storms ! The slopes were completely covered with 

 Httle furrows and gullies where the rainwater had done its 

 work. It will be a long time before vegetation will again 

 gain a foothold there and stop the washing of the earth. 



When a fire occurs in the dense forests of the Cascade 

 Range, all the trees are kiUed and the thick' layer of de- 

 caying vegetation underneath is burned. The spruce, 

 which is one of the most important lumber trees of this 

 region, does not at once spring up again. Its seeds may be 

 scattered there, but the soil is not now in a condition to 

 nourish them. In its place springs up the tamarack pine, 

 which, because it can grow in poor soil, has the whole burned 

 area to itself. 



If we should return to the same place perhaps one hun- 

 dred years after the fire, we should find that the tamarack 

 pines had formed a thick forest. The lumbermen have 

 little use for the tamarack and so have passed it by. In 

 looking carefully through the tamarack forest, we find that 

 other trees are now springing up. They are already strug- 

 gling for the food, the moisture, and the sunlight which the 

 tamaracks are making use of. 



During the many years that have passed since the fire 

 swept this region, decaying vegetation has been slowly 

 accimiulating and forming humus again. Now at last the 

 seeds of the spruce find the soil rich enough again to sprout 

 and grow. Here and there are thrifty young trees which 

 will in a few years grow up and choke out the tamarack. 

 Thus the tamarack, though of so little value itself, has done 

 a great work in preparing the soil for a new growth of the 

 valuable spruce. 



Upon the drier slopes of the Western mountains shrubs, 



