Transcript World Biomes - Tartu Veeriku Kool

World Biomes
Temperate deciduous forest
Climate
• Well-defined seasons with a distinct winter
characterize this forest biome. Moderate climate and a
growing season of 140-200 days during 4-6 frost-free
months distinguish temperate forests.
• Temperature varies from -30° C to 30° C.
• Precipitation (750-1500 mm) is distributed evenly
throughout the year.
Distribution of biome
• Temperate deciduous forests occur in eastern North
America, north-eastern Asia, and western and central
Europe.
• Most temperate deciduous forests are found in
Eastern North America somewhere around 35-48° N,
and Europe and Asia around 45-60° N.
• There are some temperate deciduous regions in the
southern hemisphere but their plants and animals are
different from those of the northern deciduous forests.
Distribution
Soil
• Brown forest soils develop
under the trees. Broadleaf
trees tend to be nutrientdemanding and their
leaves bind the major
nutrient bases. The
autumn leaf fall provides
for an abundant and rich
humus which begins to
decay rapidly in spring just
as the growing season
begins. The humus
content gives soil horizons
a brown colour.
Plants I
• Summer is a busy time for deciduous trees. Their
broad leaves capture energy from the sun and convert
it to food by photosynthesis. Some of the food is used
for growth and some is stored in the roots for next
spring.
• During the shorter days and cooler weather of autumn,
green chlorophyll in the leaves begins to decompose,
revealing brilliant oranges, yellows, and reds. Actually,
these colours were present in the leaves all year long,
but had been hidden by the green pigment of the
chlorophyll.
Plants II
• To prepare for winter, deciduous trees and plants
become dormant. They loose their leaves and seal
the places where leaves were attached with a
protective covering called a leaf scar. If they kept their
leaves, the water in the leaves would freeze into ice,
damaging the leaves and leaving the plant vulnerable
to bacteria or fungi. Plants also make a concentrated
sugar solution to stop water from freezing in their
stems.
• The longer days and warmer weather of spring signal
to the trees to grow new leaves and begin
photosynthesis again.
Oak
Sugar maple
Chestnut
Beech
Heather
Animals
• Precipitation in the temperate deciduous forest falls
throughout the year. However, during the winter
months it is usually frozen and less is available for
animals to drink. Animals living within this biome must
adjust to cold winters and hot summers by hibernating,
migrating, or keeping active all winter. Leaves fall off
trees here in the fall, leaving animals with less cover to
hide themselves from predators.
Racoon
Boar
Deer
Marten
Golden oriole
Adder
People
• Human populations are quite high in this zone (which
includes many of world's largest cities), fairly pleasant
climatically and very productive of harvestable plant
and animal life. Because the soil is excellent for
agriculture, much of it has been cleared for a very long
time all over the world for this purpose. In addition,
hardwood trees are valuable for timber, so these
forests were severely altered for thousands of years
even before extensive farming.