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 yal- 
uable as forage. These include pine grass (Calamagrostis rubescens) 
in very large amounts, timber oats grass (Danthonia intermedia), 
lupine (Lupinus serviceus) , fireweed (Chamaenarion augustifolium), 
Indian paintbrush (Castilleja cRromosa), etc. Other plants worth- 
less for forage include huckleberry (Vaccinium 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. Asarule, 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, 
