THUNDER MOUNTAIN 



909 



timber line. In fact fully 85 per cent of the land origi- 

 nally was covered with forest of greater or less density. 



The natural forest on this rugged mountain area is 

 typical of the upland regions of 

 central Idaho. In places there 

 are even today fine stands of 

 yellow pine and Douglas fir. It 

 is not uncommon to see trees 

 four or five feet in diameter. 

 Along the streams one finds 

 abundant Engelmann spruce, 

 while the most common tree is 

 the lodgepole pine, occurring in 

 some places as dense pure stands 

 and elsewhere in mixture with 

 yellow pine, spruce, and Doug- 

 las fir. Then at the higher 

 elevation, just as elsewhere in 

 the Rocky Mountains, one en- 

 counters Alpine fir and white- 

 bark pine. It was an admir- 

 able forest. It formed a pro- 

 tective cover for the steep slopes 

 and narrow ravines and can- 

 yons, and safeguarded the 

 regularity of the waterflow. 



The region is one vast water- 

 shed. Innumerable streams dis- 

 tribute water in great quantities 



into the tributaries of the Columbia River. The supply 

 of water is estimated at a minimum of approximately 



power in excess of 100,000 horsepower, which ultimately 

 can be generated. 



The watershed is being ruined. This is partly through 



TREE GROWTH PERSISTS 



Even the steepest slopes are capable of supporting trees. The character of the soil and steepness of the 

 slopes make it essential that the slopes be protected by as much forest gro.vth as possible. 



the great destruction of the forests, with the inevitable 

 efl^ect on the rapidity of the melting of the snow in the 



spring. More serious, however, 

 is the injury to the ground sur- 

 face by the excessive and utterly 

 unregulated grazing of sheep. 

 If this area had been under 

 careful regulation, it might be 

 possible to graze upon it as 

 many as 75,000 head of sheep 

 without injury to the watershed 

 and without injury to the pro- 

 ductiveness of the forest. In- 

 creasingly, stock men have been 

 rushing sheep on this area, ab- 

 solutely regardless of the effect 

 of the over-grazing on the for- 

 est range itself or upon the 

 watershed. During the past 

 season it is estimated that there 

 were about 300,000 sheep ranged 

 on the area. Not only is this 

 overgrazing destroying the bet- 

 ter grasses, but the soil is being 

 rapidly washed away. Gullies 

 are being cut that already are 

 from one to two feet deep and 

 which with every flood are being scoured out to a greater 

 width and depth. Portions of the area are described by 

 forest officers as practically a dust heap. It is said that 



SLOPE RISING ABRUPTLY ABOVE A STREAM 



These slopes today are being burned over by forest fires. Over-grazing by sheep is already starting 

 myriads of gullies which promise to have a serious effect on the stability of the waterflow. 



1,000 second feet. Many of the streams have a rapid 

 flow, averaging about 100 feet to the mile, and it has 

 been estimated by some that there is potential water- 



