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Forest Biomes
-Coniferous Forests
-Deciduous Forests
-Rain Forests
Forests
• Cover 30% of Earth land surface
• Contain 75% of Earth’s biomass
• Rain forests are most complex and diverse
biome
• Rain forests cover only 6-7% of land, but
hold 50% of land biomass and has 70% of
land species
What Do the Forests Provide Us?
Wood, paper, fruits, nuts, & beauty
They have an essential role in the earths
natural cycle by:
Absorbing Carbon
Releasing oxygen
Preventing floods
Controlling erosion
Loosing Our Forests
 Logging-each year an area the size of Florida
is lost.
 They use the timber for fuel, wood products,
industry, & farming, just to name a few.
 Because of the lack of trees in the forest-animals have no support, erosion begins,air
& water pollution.
 Acid rain destroys the trees. It weakens
them, insect and disease kill the trees.
Coniferous Forests
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Coniferous means “cone-bearing”
Coniferous trees, or conifers, produce seed cones
The cones hold the seeds
The leaf of a conifer is the needle
Needles help conserve water b/c they are long, thin
and covered in thick wax
• Most conifers are evergreen, meaning they do not lose
all their leaves at one time during the year. It happens
slowly through the entire year
• Pine, hemlock, fir, and spruce, are common in
coniferous forests
• Also aspen & birch which have broad leaves
Where
• Mostly in subarctic regions of North America, Europe,
and Asia
Climate
• Warm summers, 2-5 months
• Long, cold, dry winters
• 40-200 cm of precipitation/yr (rain in summer, snow in
winter)
Limiting factors
• Must be able to survive harsh winters, soil is frozen so
no moisture
• Soil is poor and acidic
• Ferns, lichen, sphagnum moss can grow on forest
floor
Boreal Forest - Taiga
Tree Adaptations
Taiga--slanted tree
branches to allow
snow to fall off
easily
Flexible trunks to
allow for strong
winds
Waxy resin on
needles to hold in
moisture.
Boreal Forest locations
Pine Needles
Pairs of needles
-Pine tree
Square needles
-Spruce
Flat needles
-Fir
Hemlock
-Flat triangular needles on either side
Coniferous Trees - Taiga
• 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 hemlock,
spruce, fir, and pine.
• Another 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
Evergreens
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
Podzolization
• The process by which
soils are depleted of
bases and become acidic
from leaching of pine
needles
• Podzolization occurs in
cool and moist climates
under pine forests. They
are typical of the colder
portions of the humid
continental and subarctic
climates like taiga.
Soil in the Taiga
• Soil is characterized by an upper dark
organic zone overlying a white to gray
zone formed by leaching, overlying a
reddish-orange zone formed by the
deposition of iron oxide, alumina, and
organic matter.
• Podzols form in coniferous areas or under
heath vegetation in cool, humid climates.
Animals of the Boreal Forest
Animal adaptations
• seed eaters; ex: mice, squirrels, jays,
rodents, other birds
• Insects are common in summer when
soil is moist and poorly drained
• Large herbivores feed on plants and
bark; ex: moose, elk, beaver, and
snowshoe hares
• Many species migrate, hibernate or
live under the snow
• All have thick body covers to protect
from cold
Logging in Coniferous Forests
• Large stretches of
coniferous forests in
Soviet Union and North
America haven’t been
logged because of harsh
climate
• But the need for wood is
growing
• Governments of Soviet
Union are selling these
lands because they are in
need of money
Deciduous Forests
Temperate zones
• climates with four, well-defined seasons
• Most forests in temperate zones are deciduous
examples:maple, oak, beech, ash, hickory, birch
Climate
• Temps vary greatly, 30 degrees celcius in summer to
-30 degrees celcius in winter
• Precipitation is about 50-300 cm/yr
• Precipitation is in snow or rain, and falls regularly
through entire year.
Tree adaptations
• Have to adapt to varying climate
• Growing season is about 6
months, tree grows quickly and
stores large amounts of food
• During fall, tree sheds its leaves
and becomes dormant. This
helps conserve water during
winter
• Trees feed off of their stored food
until spring, when grow new
leaves
Animals of Deciduous Forest
• Mammals that can be found include bears,
raccoons, squirrels, skunks, wood mice,
and deer. Animals like bobcats, elk, bison,
mountain lions, timber wolves, and
coyotes used to be found in the deciduous
forests, but have been hunted down by
humans and almost wiped out
Three Levels
Canopy-highest layer, made up of
upper branches and leaves of
tall trees.The canopy captures
most of sunlight, but some filters
through to bottom layers
Understory-under canopy, made of
trees that are younger and
smaller than canopy, also has
shrubsmosses, ferns, and other
plants that grow on ground layer
Forest Floor -
45
A Emergent
40 tree canopy
35
30
25 B Large trees
of Middle layer
20
15
C Lower tree
layer
10
D Shrub/small
tree layer
5
E Ground vegetation
Animals and organisms
• a deep, rich layer soil, or humus, exists because
of falling leaves decaying quickly in moist soil
which can support diverse community of
animals, insects, and organisms
• Fungi & decomposers, insects live in leaf litter
and fallen trees
• Birds, mice, small mammals feed on them
• White-tailed deer are common,
• Reptiles, amphibians, in warm forests
• Predators include: wolves, mountain lions, birds
of prey, foxes
Human Influence
• Deciduous forests
used to stretch across
Europe and Asia, and
covered eastern US
• Very little of that
remains today
• Replaced by farms,
orchards, and urban
development
Why Deciduous Forests?????
• rich soil makes it great for farmland if trees
are removed
• Deciduous trees have harder wood than
conifers, so they are better for making
furniture and flooring
• Trees also used as fuel
Replacing Deciduous Forests
• replanted to restore
• very slow, because it must also
bring back lost species
Rain Forest
• Rain forests can be found
in tropical zones-located
at latitudes near the
equator
• Receive direct rays from
sun most of the year
Climate
• Avg 25 degrees celcius ALL
year
• Growing season last all 12
months
• Precipitation is rain, except
at high mountaintops
• 200-450 cm/year
***climate does not vary or
change much in the rain forest
through the year
Structure
• Dense canopy of evergreen, broadleaf
trees supported by at least 200 cm rain
/year
• trees include: cypress, balsa, teak,
mahogany
• Ecologists have found 700 species of
trees in just 10 hectares (25 acres) of a
rain forest in Borneo
• Only 1% of sunlight will filter through to
forest floor, plants are sparse on the
floor
• Dead matter does not contribute much
nutrients to the soil because they are
recycled so quickly in rain forests due to
high moisture levels
• Nutrients are quickly drawn back into
the trees
• Topsoil is thin and poor, usually most
nutrients are in the top 5 cm
• Tree trunks are wide at the base with
buttresses-ridges for support
• Roots are shallow
• Vines grow up trees to reach sunlight,
plants can live directly on trees These
are called arboreal because they live in
trees.
Organisms and Diversity
Rainforests are the most animal diverse
biome on Earth
Two reasons:
1)diversity of plants gives high # of niches
2) wide variety of habitats in the different
levels of the forest
• Habitats vary in each level, each tree, and
each part of the tree
The Mystery Biome
• Scientists don’t know how many
species live in the rainforest
• Wilson found 43 species of ants in
one tree!
• Erwin estimated over 50 million
insect species
• Scientists continue to find more
species every time they look for
more in the rainforest
Deforestation
• destruction of forest as a result of human
activity--in 1950, more than 10% of
Earth’s land was rainforest; now it is
down to 6% and decreasing due to
destruction from developing countries,
population growth, logging, farming,
mining
• Animals habitats are quickly destroyed,
especially since the ecosystem is vertical
(goes up, not spread out)
• One acre cleared will destroy millions of
habitats
• This (biodiversity loss) is the most
serious issue with rainforest destruction
We can help save our forests by:
• Recycling - the more
paper we recycle, the
less trees we have to
be cut down.
• For every tree we cut
down, plant two more.
• Do not purchase
products made of
wood or purchase the
at a higher quality so
they last longer.