TtlE WESTERN VALLEYS 123 



this region. They are largely localized and may be separated 

 or surrounded by tracts in which far different conditions obtain. 

 They are found in the valleys and canyons and on the lower 

 slopes of the Flathead drainage, in parts of the Kootenai Valley, 

 and in the northern part of the Bitter Root Range between Mon- 

 tana and Idaho. They are found at their best, as far as the 

 writer's observations have extended, in the valley of the Swan 

 River, and some other tributaries of the Flathead, where they 

 diminish and merge into the drier land formations southward 

 along the east side of Flathead Lake, and in the valley of the 

 Priest River in northern Idaho. In Ulacier Park they are to 

 be found in Avalanche Basin, and the valley of McDonald Creek 

 and in other places west of the Continental Divide. The best 

 forests of the Flathead are along the upper courses of its main 

 branches and their many tributaries among mountains and in 

 narrow gorges ; the river in its lower course enters the open coun- 

 try where the mesophytic forests gradually yield to more and 

 more xerophytic types. Very little is seen of Finus monticola 

 and its associates below the upper end of Flathead Lake until 

 the slopes of the Bitter Root are reached. The western slopes 

 of this range and the neighboring country of the St. Joe and the 

 Clearwater of Idaho are covered by some of the best of the white 

 pine forests of the northern Rocky Mountain region and this 

 species and some of its associates have crossed to the eastern 

 slope and descended into the valley of the St. Regis and other 

 tributaries of the Clark's Fork. All of this section of Montana 

 from the Kootenai to the St. Regis occupies but a corner in the 

 northwestern part of the state. 



Some discussion of the leading species in the white pine 

 forest may now be appropriate. The white pine as the most 

 characteristic element will be taken first. Its salient features 

 may be summed up as follows : 



The seeds are well adapted to wind dispersal. The trees 

 show considerable tolerance while young and grow rapidly in 

 height. The species seems impartial as to structure and com- 

 position of the soil. The above are the positive qualities. Op- 

 posed to these are the facts that seeds are produced sparingly 

 and rarely if at all until the trees are 40 to 60 years of age. The 

 seeds germinate slowly, have low percentage of germination and 



