The Black Hills, Bear Lodge Mountains, and Devils Tower - Mountains and Plains: The Ecology of Wyoming Landscapes - page 272

pole pine and limber pine, both very common in the
Rocky Mountains to the west, are found in only one
or two localities in the Black Hills. engelmann spruce,
subalpine fir, and Douglas-fir are not found there at all.
the Black Hills region has four kinds of deciduous
woodland: riparian, woody draws, bur oak, and aspe n. 17
the first, found in ravines and along rivers at low eleva-
tions, is dominated by boxelder, green ash, hackberry,
bur oak, American elm, and plains cottonwood. 18
Woody draws are found nearby and have thickets of
chokecherry, American plum, currant, Woods' rose,
hawthorn, western snowberry, red osier dogwood, and
various willows (see fig. 10.12). Historical photographs
suggest that these woodlands were more dense before
livestock grazing and farming began.
the third type of deciduous woodland occurs on the
upland at lower elevations and is dominated by bur oak
(see fig. 16.6). it occurs most often in the northern and

Fig. 16.7. White spruce is common in the Black Hills at high
elevations and along valley bottoms with cool-air drainage. it
is rare in the Bear Lodge Mountains.

Fig. 16.6. Bur oak is found at lower elevations in the Bear Lodge
Mountains and Black Hills, sometimes growing under an open
canopy of ponderosa pine. this photo was taken on the east
slope of the Bear Lodge Mountains. elevation 4,250 feet.

common plants associated with the pine and oaks are
aspen, chokecherry, common juniper, mountain nine-
bark, paper birch, and white spruce.
in all localities, fire suppression has led to an increase
in the density of ponderosa pine, with highly flam-
mable forests now found in many areas . 15 Most of the
forests are second growth, having been subjected to log-
ging for many years. An outbreak of the mountain pine
beetle has killed many of the trees during the past 10
years, but dwarf mistletoe is rare or absent . 16
White spruce groves are found in canyons and
ravines, on north-facing slopes, and in cooler, wet-
ter habitats at higher elevations (fig. 16.7). in espe-
cially humid locations, such as on the north slopes of
ravines, the tree branches sometimes are draped with
a lichen known as old Man's Beard ( Usnea cavernosa
and U. sorediifera ). Spruce occurs on both igneous and
limestone substrates, commonly in close proximity
with ponderosa pine, aspen, and paper birch. Lodge-