Because the climate
of the taiga is very cold, there is not a large variety of plant
life. The most common type of tree found in the taiga is the conifer--trees
that have cones. Four kinds of conifers are common in the taiga.
Three of the common conifers are evergreens; spruce, fir, and pine.
The fourth common conifer is the tamarack, or larch, a deciduous
tree. Under certain conditions, broadleaf trees, such as birch and
aspen, are able to survive the harsh climate of the taiga.
Photo: Evergreen and deciduous conifers. Insert is a branch section
of a deciduous conifer. Photos
© Gayle W. Croft.
Evergreens use a wide variety of physical adaptations. Some of these
adaptations include their shape, leaf type, root system, and color.
Their name, evergreen, describes an important adaptation. They are
always--or ever green. Because they don't drop their leaves when
temperatures cool, they don't have to regrow them in the spring.
new leaves takes a lot of energy. Plants
get their energy from the soil and from
the Sun. Soil is a source of nutrients.
Sunlight is necessary for photosynthesis
to take place in the plant. The taiga
soil doesn't contain many nutrients, and
the Sun usually remains low in the sky.
These two factors limit the amount of
energy available to the tree. By keeping
their leaves, the evergreens are able
to use that limited energy for structural
growth rather than producing leaves.
the taiga has moderately high precipitation, the ground freezes
during the winter months and plant roots are unable to get water.
The adaptation from broadleaf to narrow needle-like structures limits
water loss through transpiration. Evergreen needles do not contain
very much sap. This limits the risk of needle damage from freezing
temperatures. The needles do, however, contain a chemical that repels
animals who would eat the needles. The dark green color of the needles
absorbs the sunlight, and since the needles are always present,
once temperature start to get warm, photosynthesis quickly begins.
The conical shape of the evergreens allows the snow to slide off
the branches rather than pile up. If the snow can't pile up on the
branches, there is less risk of broken branches due to the weight
of the snow. Photo © 2000-www.arttoday.com