514 forestry Quarterly. 



there is also a question as to the possible change in the area occu- 

 pied by each during the past and what the effect of fire protec- 

 tion is likely to be in the future. 



That the area occupied by Lodgepole Pine has been increasing 

 seems very probable. This is indicated in places by scattering 

 understories of young Lodgepole Pine under old Yellow Pine 

 stands and in other places by even-aged stands of Lodgepole Pine 

 on sites which are typical for Yellow Pine. An excellent example 

 of the changing forest type may be seen in Sections 23, 24, 25 and 

 26 of Township 24 S., Range 11 E. At first this locality appears 

 to be a pumice flat in which there are traces of an old Yellow 

 Pine forest. A closer examination shows numerous slight irreg- 

 ularities in the surface and many small rock outcrops, indicating 

 that the pumice cover is very thin. On this area there are still a 

 very few scattering old Yellow Pine and occasional half rotten 

 logs and stumps, showing plainly that there has been at some 

 time a considerable Yellow Pine stand. The forest at present 

 consists of two generations of Lodgepole Pine : the first standing 

 out distinctly as scattered old trees with dense, widespreading 

 crowns which reach to the ground showing that they have grown 

 in a very open stand. The second generation is much younger 

 and forms a close, rather even-aged stand characteristic of the 

 species. In this instance there is shown a complete change from 

 Yellow Pine to Lodgepole Pine with every indication that the 

 Lodgepole Pine will be the permanent type. It is probable that 

 the Yellow Pine was killed by fire and that the first generation 

 of Lodgepole Pine came in from an understory that was de- 

 stroyed with the Yellow Pine. The second generation of Lodge- 

 pole Pine is the result of seeding from the first scattering stand 

 which came in after the fire. 



There are numerous indications that Lodgepole Pine is increas- 

 ing in other places, but nothing to show definitely that Yellow 

 Pine is restocking any territory. It is not uncommon to find 

 single Yellow Pine seedlings on the typical Lodgepole Pine flats 

 but it is not probable that they will ever reach maturity. 



Unfortunately the data secured on this subject are not very 

 extensive but a careful consideration of all available material has 

 led to the conclusions, first, that the distribution of Yellow Pine 

 in this region is dependent almost entirely on the depth of the 

 water table; second, that the distribution of Lodgepole Pine on 



