28 BULLETIN 154, U. S. DEPARTMENT OF AGRICULTURE. 



GROUND COVER. 



Lodgepole stands, particularly in Montana and northern Wyoming, 

 have a ground cover of grasses and weeds, many of which are val- 

 uable as forage. These include pine grass (C 'alamagrostis rubescens) 

 in very large amounts, timber oats grass {Danthonia intermedia), 

 lupine (Lupinus serviceus) , fireweed (C hamaenarion augustifolium) , 

 Indian paintbrush (Castilleja chromosa), etc. Other plants worth- 

 less for forage include huckleberry (Vacdnium scoparium) , which is 

 especially abundant on the poorer sites, arnica (Arnica cordifolia) , 

 and elk grass (Xerophyllum tenax). In moist places alder (Alnus 

 tenuifolia) and willow frequently occur as underbrush. The forage 

 plants are less abundant in Colorado and southern "Wyoming and the 

 huckleberry more prevalent. Ordinarily fallen leaves disintegrate 

 so rapidly that there is no accumulation of duff from this source. In 

 mature stands there is very little litter as a rule, and one can ride 

 through them almost anywhere. 



AGE CLASSES. 



A striking characteristic of lodgepole-pine forests is their even 

 age. This, of course, is due to the fact that most of the present 

 stands have originated as a result of fire, followed almost imme- 

 diately by reproduction. As a rule, the burned areas thoroughly stock 

 in a few years, though sometimes the reproduction is very open, the 

 blanks filling in slowly with young growth and so producing an 

 uneven-aged stand. Young stands often contain a few older trees, 

 most of them limby and fire-scarred at the base, which have man- 

 aged to escape destruction. 



Clear cutting is usually followed by even-aged stands, though the 

 reproduction is apt to be slightly slower in establishing itself, par- 

 ticularly if fire is kept out. Some areas cut over 20 years ago now 

 have their blanks filled from seed produced by the rather scattered 

 reproduction which followed the cutting. 



All the trees in even-aged lodgepole forests are not necessarily 

 of the same size. Unless the stand is so dense as to cause stagnation 

 some seedlings, especially on the more favorable sites, get a better 

 start and develop more rapidly than others. A small, suppressed tree 

 often may be as old as another more vigorous one at its side two or 

 three times as large in diameter. 



Fires have been so frequent in the region that they have brought 

 about a wide range of age classes in the lodgepole zone as a whole. 

 In Montana most of the stands are comparatively young. Figures 

 collected there show that approximately two-thirds of the timbered 

 area is now covered with nonmerchantable, immature growth, while 

 the merchantable timber on the remaining third is partly immature, 



