7 
294 BOTANICAL GAZETTE [APRIL 
caulis. Scattered specimens of juniper are found in places.. In 
other respects the forest is like the other stands in the mesophytic 
regions. 
In what has been said concerning fires, no mention has been made 
of species other than conifers. They may often play an important 
role in the first stages in the natural process of reforestation, but their 
importance diminishes as the life history becomes complete. One of 
the first plants to give a decided aspect to the forest after fires is the 
fireweed (Chamaenerion angustijolium). The birch and aspen, by 
virtue of their light seeds, gain an early place in the burns. Indeed 
sometimes their stands become quite dense and they check the advent 
of coniferous species. Many species that were on the forest floor of 
the mature stand may have survived the fires and spring up even 
more vigorously than before, because the shade has been removed. 
Especially is this true of those forms that can send shoots from their 
roots or from underground stems. In the burn on the east slope of 
the Mission Range south of Big Fork, there are shrubby growths of 
Salix spp., Ceanothus sanguineus, Opulaster pauciflorus, Acer 
glabrum, and Holodiscus ariaejolia, many of which probably were 
present as underbrush in the stand that existed previous to the burn. 
These shrubs will retard the reforestation of the area in some instances 
to a marked degree. If the forest that is destroyed be on the border 
of the prairie, plants from that association will form an important 
element in the growth that follows. This is of course detrimental to 
forest growth. Indeed if the fires be repeated often enough, the 
forest plants will gradually diminish in quantity, and the prairie 
element will become more and more prominent, until finally a prairie 
will come to replace a forest. If the fires be checked, however, for 
any length of time, the forest will gradually reconquer the territory 
thus lost. It is probable that some of the prairie region in Flathead 
valley has been won from the forest in this manner. It must be 
remembered that in the area bordering on the prairie, in Flathead 
valley at least, lodgepole pine is not successful and is thus ruled out 
from playing any important réle in these places after fires. 
In the discussion of the causes for the Nigger Prairi 
mention was made of the importance of the accumulation of hum 
in rendering the sandy soil more capable of holding moisture. 
e region, 
us 
It 
