56 BOTANICAL SURVEY OP THE C(EUR D'ALENE MOUNTAINS. 



FOREST ZONES. 



^ To obtain an accurate conception of the Cceur d'Alene forests as we 

 find them now, and to enable us to treat the subject comprehensively, 

 it is necessary that a division into zones or districts be made. There 

 are various advantages in such a partition. Jt will enable us to treat 

 each part specifically, and when we come to consider the problems con- 

 nected with the destruction and preservation of the growing timber 

 we can the more readily refer to any of the various sections comprising 

 the same. I propose to make two classifications of the coniferous for- 

 ests of the C<eur d'Alenes, basing them upon (1) the vertical range of 

 the species; (2) upon the age of the trees which predominate over any 

 given area. The former of these is the plan generally used in moun- 

 tainous regions to define the presence or absence of species within cer- 

 tain limits. The latter has, so far as I am aware, never been employed 

 m the West to characterize the condition of the general forest growths 

 over large areas. It is, however, by far the best and most reliable from 

 an economic point of view, and, as it is applicable to all our Western 

 timber regions alike, should be employed in all cases where an accurate 

 knowledge of the condition of the forest is desired. Both classifications 

 will apply to any of the forests of the Pacific Slope. Hut there is this 

 to be observed, that the limitations of the former will always vary with 

 the species which compose the forests and the latitude of the region 

 where they grow, while the latter can be applied alike to all areas* no 

 matter where situated. For this reason, if we wish to know the actual 

 state of the forest growth of any region of the West on a basis of these 

 divisions, we must have a table of the vertical limitations of the forest 

 zones of such locality, (liven this, with the data of age demanded by 

 the second division, we should be able to form a very accurate concep- 

 tion of the true condition of the forest anywhere. 



According to the first principle of classification, namely, the species of 

 conifer which is most abundant or characteristic in each section, the 

 forests may be divided into four parts. They will be designated thus : 

 The Lower, or Zone of Yellow Pine {Finns ponderosa)- the Interme- 

 diate, or Zone of White Pine (Pinm monticola) ; the Upper, or Zone of 

 Subalpine Fir (Abies Imiocarpa) ■ and the Crest Line, or Zone of White- 

 barked Pine (Pinus albieaulh). 



^ The second classification will give us four categories : Old Growth 

 Second Growth, Young Growth, and Recent Burns. 



It must not be understood that these sections are absolute in their 

 limitations. Innumerable variations and modifications are found to 

 occur when each is taken up specifically. Ibit in general they will 

 stand, and are infinitely preferable to the customary '-lumping" of the 

 forest region into one very heterogeneous mass. 



In attempting to limit the vertical extension of the coniferous forest 

 zones of the OcBur d'Alenes we meet at once with a serious difficulty. 



