Average monthly precipitation in cm14
12
10
8
6
4
2
0
Months1015205
0
–5
–10
–15
–20
–25
–30Average monthly temperature in°CJFMAMJJASONDRAYMOND GEHMAN/NG Image CollectionBased on data from http://www.worldclimate.comBoreal Forest
Just south of the tundra is the boreal forest, or
northern coniferous forest (also called taiga,
pronounced tiéguh). Boreal forest stretches
across North America and Eurasia. There is
no biome in the Southern Hemisphere com-
parable to the boreal forest. Winters in the bo-
real forest are extremely cold and severe, although not as
harsh as those in the tundra. Boreal forest receives little
precipitation, perhaps 50 cm (20 in) per year, and its soil
is typically acidic and mineral poor, with a thick surface
layer of partly decomposed pine and spruce needles. Per-
mafrost occurs only in patches, often deep under the sur-
face. Boreal forest has numerous ponds and lakes dug by
ice sheets during the last ice age.
Black and white spruces, balsam fir, eastern larch, and
other conifers dominate the boreal forest, although decid-
uous trees (trees that shed their leaves in autumn), such as
aspen and birch, may form striking stands (Figure 6.5).
Conifers have many drought-resistant adaptations, such as
needle-like leaves whose minimal surface area prevents wa-
ter loss by evaporation. Such an adaptation helps conifers
withstand the drought of the northern winter,
when roots cannot absorb water through the
frozen ground. Being evergreen, conifers re-
sume photosynthesis as soon as warmer tem-
peratures return.
The animal life of the boreal forest consists
of some larger species such as caribou, which
migrate from the tundra for winter; wolves;
brown and black bears; and moose. However, most boreal
mammals are medium sized to small, including rodents,
rabbits, and smaller predators such as lynx, sable, and
mink. Birds are abundant in the summer but migrate to
warmer climates for winter. Insects are plentiful, but few
amphibians and reptiles occur except in the southern bo-
real forest.
Most of the boreal forest is not well suited to agricul-
ture because of its short growing season and mineral-poor
soil. However, the boreal forest yields lumber, pulpwood
for paper products, animal furs, and other forest prod-
ucts. Currently, boreal forest is the world’s top source of
industrial wood and wood fiber. Extensive logging, gas
and oil exploration, mining, and farming have contrib-
uted to loss of boreal forest.Ài>ÊvÀiÃÌÊUÊ}ÕÀiÊÈ°xÊThese coniferous forests occur in cold regions of the Northern Hemisphere adjacent to the tundra. Photographed in Saskatchewan,
Canada. Climate graph shows monthly temperatures and precipitation for Fort Smith, Northwest Territories, Canada.
boreal forest A
region of coniferous
forest (such as pine,
spruce, and fir) in the
Northern Hemisphere;
located just south
of the tundra. Also
called taiga.Interpreting Data
Do changes in average monthly temperatures in this boreal
forest correspond to any noticeable changes in average
monthly precipitation? If so, what are those trends?