54 SURVEYS OF FOREST RESERVES. 



Fire lias destroyed, for the present, the productiveness of perhaps half of the 

 reserve. 



Questions of water supply are important on the eastern slope. 



Mining has attained some development, and is likely to increase. 



Agriculture practically does not exist within the reserve. 



Grazing is not important except in scattered localities on the western slope. 



The commercial development of the eastern slope should he provided for at once. 



The Bitterroot Forest Eeserve includes the crest and slopes of the 

 continental divide in the southern portion of the Bitterroot Mountains 

 in west-central Montana and east-central Idaho. Its length from north 

 to south is about 105 miles, its breadth from east to west about 85 miles, 

 and its boundary includes an area of 4,147,200 acres. Prom this total 

 there must be subtracted 256,360 acres of railroad land, besides an 

 unknown, but very small area of mining locations and a few agricul- 

 tural and timber claims. The continental divide separates the reserve 

 into two parts so distinct from each other that they demand separate 

 treatment. 



EASTERN SLOPE. 



The eastern slope of the Bitterroot Eeserve embraces an exceeding'ly 

 broken mountain region descending abraptly to the level and fertile 

 Bitterroot Valley. It is traversed by nearly straight canyons of great 

 depth, usually with precipitous sides cut through the granite by gla- 

 ciers which have now disappeared. It is estimated to include about 

 80,000 acres. North of the West Fork of the Bitterroot Eiver the 

 rock is granite. To the south the granite is replaced by quartzite and 

 felsitic rocks which contain almost the only known mineral deposits. 

 The climate is severe, but not conspicuously moist. Large amounts of 

 timber have been cut from the reserve, and from the timber lands adja- 

 cent by the Bitterroot Development Company (now the Anaconda 

 Copper Mining Company) chiefly for the use of their mines at Ana- 

 conda and Butte. At the time of my visit in July and August, 1806, 

 they were shipping daily, from their mill at Hamilton, one train of about 

 twenty-four cars loaded chiefly with mining timbet. 



As much of the area of the Bitterroot Valley as can be irrigated is 

 valuable agricultural land. Dams have been built on Mill Creek and 

 Big Creek, and others will probably follow on other tributaries. 



THE FOREST, EASTERN SLOPE. 



The forest is comparatively open, and more or less sharply separated 

 into two forest types. Of the tirst, the characteristic tree is the west- 

 ern yellow pine, which is said to cover about one-third of the area 

 occupied by this type, while the red fir covers most of the remaining 

 two-thirds. Higher up it is replaced by Ihe high mountain lodge-pole 

 pine type of forest. About 90 per cent of this forest is occupied by the 

 tree from which it takes its name. 



The yellow pine in the Bitterroot Valley reproduces itself with a 

 vigor and persistence not known in many portions of its habitat. 

 Toang trees are common in the lower portions of the valley outside of 

 the reserve, and at lower elevations in the reserve itself This tree 

 reaches average dimensions as follows: Height, 90 feet; diameter, 2 

 feet; length of clear trunk, 40 feet. It is chiefly used for lumber. It 

 is estimated that nearly 50 per cent of all the trees of this species are 

 here unsound, as the result of forest fires. 



