The Black Hills, Bear Lodge Mountains, and Devils Tower - Mountains and Plains: The Ecology of Wyoming Landscapes - page 276

toward fire continues, fostered for many years by one-
sided Smokey Bear ads and by fires sometimes spread-
ing onto private land from national parks and national
forests. Yet the negative effects of fire suppression have
moderated those views, and prescribed fires are now
common on both private and public lands. 41
However, fire management plans are not easily imple-
mented. Some forests have become so dense that uncon-
trollable crown fires develop easily. often the labor of
tree thinning and removal is preferred (fig. 16.11). Pre-
scribed burning in grasslands also poses significant
challenges. For example, fires are usually kept small so
that they can be extinguished easily if weather condi-
tions change unexpectedly, but the new regrowth of
burned grasslands typically attracts bison and cattle. if
the burns are too small, excessive grazing of the new
plant growth results.
Another challenge, in the Black Hills and other parts
of the Rocky Mountain region (see chapter 12), is the
large number of homes and communities dispersed
through most of the Hills. Managers hesitate to ignite
prescribed fires where homes are nearby. Such fires
almost always burn within the agreed-to limits of the
managers, and almost always they can be put out at
will. However, there are still risks. consequently, pre-
scribed fires are used less often than some managers
would like. And when they are ignited, when weather
conditions are “favorable,” the slow-moving fires usu-
ally burn only a small portion of the area that would
benefit from burning. the conundrum is that overly
cautious prescribed fire causes higher risks of wildfire
in the future. 42
Fuel loadings are clearly an important factor con-
tributing to flammability in low-elevation ponderosa
pine forests, but weather is important as well. Peter
Brown examined fire scar data from sites distributed
throughout the Black Hills and found that the years
with the most fires were associated with drought s. 43 H e
also found that new seedlings of ponderosa pine were
more likely to become established during wet periods,
with the most extensive recruitment associated with an
extended wet period from the late 1700s to early 1800s.
From this he concluded that even-aged cohorts often
become established because of a sequence of favorable
climatic conditions, not catastrophic fires or the initia-
tion of fire suppression.

Fig. 16.10. Ponderosa pine seedling density can be high after
a period of weather conditions that favor seedling establish-
ment. if surface fires occur frequently enough, the young trees
are killed before a highly flammable forest develops.

increased tree density and forest expansion are also
thought to have caused a reduction in streamflow, as
evapotranspiration is higher in forests and woodlands
than in grasslands. 39 Watershed managers know that
streamflow increases after tree cutting or burning (see
chapter 12). the journals of early explorers suggest that,
in the 1800s, there were more beaver, greater water stor-
age capacity in the stream banks, more plant growth
in widespread riparian meadows, and possibly more
streamflow (but fewer flash floods).40 40
the value of periodic surface fires for maintaining
grasslands, savannas, and more open forests is now
widely recognized. Among the benefits are reduced
fuels, a lower probability of hard-to-control crown
fires, and more streamflow and forage production. Also,
native plants are maintained, thereby reducing the
likelihood of invasive plants. negative public opinion