Coniferous Forests
Coniferous
forests are made up mainly of cone-bearing or coniferous trees, such as
spruces, hemlocks, pines and firs. The leaves of these trees are either
small and needle-like or scale-like and most stay green all year around
(evergreen). All are softwoods able to survive cold temperatures and
acidic soil.
Coniferous
forests are found mainly in the northern hemisphere, although some are
found in the southern hemisphere.
The
northern coniferous forests are called taiga or boreal forests. They
cover vast areas of North America from the Pacific to the Atlantic, and
range across northern Europe, Scandinavia, Russia and across Asia
through Siberia and Mongolia to northern China and northern Japan.
Short summers and long winters
Coniferous
trees thrive where summers are short and cool and winters long and
harsh, with heavy snowfall that can last as long as 6 months. The
needle-like leaves have a waxy outer coat, which prevents water loss in
freezing weather and the branches are soft and flexible and usually
point downwards, so that snow slides off them. Larches are one example
of a coniferous tree found in some of the coldest regions. Unusually
for coniferous trees they are deciduous, that is they shed their leaves
in winter.
Coniferous
trees such as cypresses, cedars and redwoods are found in warmer
regions.
Life on the forest floor
Even
evergreen trees eventually shed their leaves and grow new ones. The
needles fall to the forest floor and form a thick springy mat.
Thread-like fungi help to break down or decompose the fallen needles.
These fungi provide nutrients from the decomposed needles back to the
roots of the trees. But because pine needles do not decompose easily,
the soils are poor and acid.
These
forests grow under widely differing conditions of climate and soil -
from the tropics to the subarctic, and from heavy clays to poor sands.
However, coniferous trees are especially conditioned to the winter
climate. The trees of the taiga grow at the highest latitude of any
forest. The most common are spruce, pine and firs.
Reach for the sky!
Cypresses,
cedars and redwoods grow upright; the tallest of them can reach 20m in
height. The trees are usually pyramid-shaped. Short, lateral branches
grow quite close together but they are so flexible that the snow simply
slides off. The leaves are small, hard and evergreen.
Little
light penetrates the thick canopy of
trees to reach the forest floor. Because of this gloom, only ferns and
a few herbaceous plants grow here. Mosses, liverworts and lichens are
also found on the forest floor and grow on tree trunks and branches.
There are few flowering plants.
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