Download Trees and Forests

TREES AND FORESTS
Topic E
IDENTIFY REASONS
WHY TREES AND
FORESTS ARE VALUED
The Value of Forests and Trees
•
Trees and forests are important to living things on Earth.
•
Trees and forests are valued for the following reasons:
•
•
•
•
•
•
•
•
•
•
•
They produce oxygen and use the carbon dioxide from the air. Carbon dioxide is one of the
greenhouse gases that may cause global warming.
They are able to filter out harmful pollutants from the air that everyone breathes.
They produce food products used by humans.
They provide food and homes for a variety of animals.
They serve as a windbreak from strong winds.
They give shade and protection from direct sunlight. Also, the transpiration in a forest cools
the environment like an air conditioner.
They produce natural ingredients that are used for medicines.
They provide raw materials for the construction of buildings and paper products.
They provide areas for recreation, such as camping and other outdoor activities.
They help prevent soil erosion. Tree roots spread out and hold the soil in place.
They enrich the soil with chemical nutrients when dead leaves decompose.
The Value of Forests and Trees
•
Forests serve as habitat for a variety of living things and are important to human
needs for recreation, for raw materials, and for a life-supporting environment.
Which of the following statements about
trees is false?
A.
Trees provide food.
B.
Trees provide oxygen.
C.
Trees make the air moister.
D.
Trees make the air warmer.
Lily was camping with her family. She noticed
that all of the picnic tables in the campground
were located underneath tall trees.
The picnic tables were most likely located
underneath the trees because the trees:
A.
Supply dead leaves for fires.
B.
Prevent animals from eating the food.
C.
Filter pollutants and give off carbon dioxide.
D.
Give shade and provide protection from sunlight.
Use the following information to answer
the next two questions.
At one time, western Ireland was covered by oak forests. Several hundred years
ago, all the oak trees were cut for building materials. The forests have never grown
back. The land is now mostly bare rock with little soil.
Which of the following statements best
explains why the land in western Ireland is
mainly bare rock, with little soil?
A.
The soil has hardened to rock.
B.
Soil was removed by farmers for their fields.
C.
Without trees, the soil was lost by wind and water erosion.
D.
The land was always mainly rock, even when the forests were there.
According to the given information, this
change in Ireland’s landscape occurred as a
result of the fact that oak
A.
Is very expensive.
B.
Is beautiful wood.
C.
Is useful for building.
D.
Must be cleared for farms.
Use the following descriptions to answer
the next question.
Diane’s teacher asked Diane to identify the benefits of trees from the following list.
1.
Provide food for humans
2.
Make the air drier
3.
Make the air cooler
4.
Can be made into plastic
5.
Provide homes for many animals
6.
Made into paper
7.
Can be used to make lumber
Listed in numerical order, the benefits in the
given list that describe spruce trees are:
_______, ________, ________ and ________.
Use the following information to answer
the next question.
Theresa spent some time learning about her Cree heritage. She learned that the
Cree people had many uses for poplar trees. Through her research, Theresa found
the following information about poplar trees:
•
A tea made from poplar shoots contains the chemical bisabolol, which kills the
bacteria that cause the lung disease tuberculosis.
•
A tea made from the buds of balsam poplar trees contains a chemical similar to
the drug in aspirin.
•
When a paste made from the bark of poplar trees is applied to boils, it draws out
infection.
•
The inner bark of poplar trees can be rubbed on muscles to take away soreness..
The given uses of the poplar trees could
be best classified as:
A.
Economic
B.
Medicinal
C.
Nutritional
D.
Recreational
The overall relationship between the animals
and trees in a forest can be described as:
A.
Harmful
B.
Parasitic
C.
Cooperative
D.
competitive
Which of the given objects is not made
from some part of a tree?
A.
Tissue (Kleenex)
B.
Chewing gum
C.
Glass
D.
cork
Barred owls live in densely forested areas all
across Canada.
Barred owls make their home in which of the
following layers of the forest?
A.
Canopy
B.
Shrubbery
C.
Understory
D.
Forest Floor
DESCRIBE KINDS OF
PLANTS AND ANIMALS
FOUND LIVING ON, UNDER
AND AMONG TREES; AND
IDENTIFY HOW TREES
AFFECT AND ARE AFFECTED
BY THOSE LIVING THINGS
Parts of the Forest
•
The forest is made up of different layers.
•
In each layer, there are plants and animals found living on, under and among trees.
Canopy
•
The first forest layer is the canopy.
•
The canopy is a very thick blanket of treetops that captures more than 90% of the
sunlight.
•
This is the place where photosynthesis occurs.
•
A lot of flying animals, such as warblers, owls and insects (butterflies, aphids), can
be found in the canopy.
•
Squirrels make their nests in the canopy.
Understory
•
The second layer of the forest is called the understory.
•
Many small trees, large bushes, and the trunks of large trees are found in this
layer.
•
This layer also provides a sheltered space for many forest animals.
Shrubbery
•
The third layer is the shrubbery layer.
•
The shrubbery layer is home to many forest wildflowers, small shrubs, and
grasses.
•
Deer, skunks and rabbits find their food on this level.
Forest Floor
•
The last level is the forest floor.
•
The forest floor is dark and damp.
•
Only plants that can live with very little light grow here.
•
Branches and leaf litter fall from the trees, and animal feces collect on the forest
floor.
•
Bacteria and fungi decompose these materials.
Fungi
•
Fungi are not plants and they do not have chlorophyll.
•
They do not produce their own food through photosynthesis.
•
Instead, fungi get their nutrition from dead plant material.
•
Mushrooms, conks, and lichens are examples of fungi.
Bacteria
•
Soil bacteria are the main bacterial decomposers found in a forest.
•
Scavengers or detritivores, such as worms and millipedes, are hard at work in the
soil helping the decomposers break down dead matter.
Other Inhabitants of the Forest Floor
•
Inhabitants of the forest floor also include toads, mushrooms, and insects.
The Forest is a Habitat
•
Forests serve as a habitat for a variety of living things.
•
A habitat is an area or environment in which an organism or ecological
community normally lives or occurs.
•
An ecosystem consists of a living community that depends on each member and
its surrounding environment.
•
A forest is an example of an ecosystem in which living and non-living things
interact.
Producers, Consumers and Decomposers
•
The living things in a forest are categorized into three groups: producers,
consumers and decomposers.
•
Producers are living things that use energy from the sun to produce their own
food.
•
Plants are producers.
•
Consumers are living things that need to eat producers (plants) to live.
•
There are three types of consumers: herbivores, carnivores and omnivores.
•
Decomposers are living things that feed off dead plants and animals.
•
They reduce remains to mineral nutrients for the soil.
•
Mushrooms (fungi) and bacteria are types of decomposers.
Types of Consumers
•
Herbivores are animals that eat plants.
•
Eg: Deer, squirrels and caterpillars
•
Carnivores are animals that eat other animals.
•
They are considered consumers because they need to eat herbivores to survive.
•
•
Eg: Lynx, coyotes, and wolves
Omnivores are animals that eat both plants and animals.
•
Eg: Bears and foxes
Non-Living Things in the Forest
•
Non-living things in a forest includes:
•
•
•
•
•
•
Water
Rocks
Sunlight
Air
Soil
chemicals
Use the following information to answer
the next question.
The fungus that grows in living and dead trees can be a source of food for many
insects. Beetles and other insects burrow into trees to eat the fungus. Woodpeckers
make holes in the trees to find beetles to eat.
Which of the following food chains is
described in the given information?
A.
Air
tree
beetle
woodpecker
B.
Soil
tree
beetle
woodpecker
C.
Tree
fungus
beetle
woodpecker
D.
Tree
beetle
fungus
woodpecker
The original source of energy used by
trees is the
A.
Air
B.
Sun
C.
Soil
D.
water
Which of the following tables matches each
animal with the type of consumer it is?
Horse
Carnivore
Horse
Carnivore
Lion
Omnivore
Lion
Herbivore
Human
Herbivore
Human
Omniovre
Horse
Omnivore
Horse
Herbivore
Lion
Carnivore
Lion
Carnivore
Human
Herbivore
Human
Omnivore
The forest layer in which deer, skunks and
rabbits are found is the
A.
Canopy
B.
Shrubbery
C.
Understory
D.
Forest floor
Which of the following statements about
decomposers is true?
A.
Decomposers are non-living things that reduce mineral nutrients in the soil.
B.
Decomposers are non-living things that increase mineral nutrients in the soil.
C.
Decomposers are living things that reduce the mineral nutrients added to the soil.
D.
Decomposers are living things that increase the mineral nutrients added to the soil.
Organisms that are consumers are
classified as
A.
Deciduous and coniferous
B.
Sunlight, air, soil and chemicals
C.
Maggots, beetles and earthworms
D.
Herbivores, carnivores and omnivores
The loss of even one species can ruin an entire forest
ecosystem of plants and animals. The organisms that
depend on this missing species as prey lose their food
source. In turn, the organisms that it fed on lose a
predator.
If robins were removed from a forest ecosystem, the
initial impact on the forest would most likely be
A.
An increase in the population of rabbits, followed by a decrease in the population of
mice
B.
A decrease in the population of rabbits, followed by an increase in the population of
mice
C.
An increase in the population of caterpillars, followed by a decrease in the number of
poplar leaves
D.
A decrease in the population of caterpillars, followed by an increase in the number of
poplar leaves
Which of the following food chains could exist in a
forest?
A.
Moose
hare
lynx
deer
B.
Hare
coyote
deer
plants
C.
Plants
hare
coyote
wolf
D.
Squirrel
grouse
coyote
deer
When Ter was hiking through a forest, he observed
different types of mushrooms growing from the sides of
trees and on the forest floor. Ter knows that mushrooms
are a type of decomposer called fungi.
Which of the following statements describes what would
most likely happen if all the decomposers in a food web
were removed?
A.
The flow of nutrients would stop
B.
The flow of nutrients would continue
C.
The herbivore population would increase
D.
The carnivore population would increase
In the forest ecosystem, wildflowers act as
A.
Decomposers
B.
Herbivores
C.
Omnivores
D.
producers
DESCRIBE THE ROLE OF
TREES IN NUTRIENT CYCLES
AND IN THE PRODUCTION
OF OXYGEN
The Role of Trees in the Nutrient Cycle
and Oxygen Production
•
Plants make food for themselves and others.
•
This is why they are called producers.
•
Plants use the energy from the sun, water from the soil, and gases in the air to
make their food.
•
Plants also need chemicals or mineral nutrients to grow.
•
The mineral nutrients are like the vitamins you may take for healthy growth.
•
Mineral nutrients are carried in the water from the soil.
Animals
•
Animals need food and mineral nutrients as well.
•
They cannot make their own food or use minerals directly from the soil.
•
They need to eat plants to get food and mineral nutrients.
•
Animals that do not eat plants will eat animals that have eaten plants.
•
This way, they get the food and mineral nutrients they need to live and grow.
•
Animals that consume, or eat, other living things are called consumers.
Decomposers
•
Eventually, plants and animals die.
•
The chemicals that made up their bodies are returned to the soil by decomposers.
•
Decomposers are bacteria and fungi that break down dead matter.
•
They replace the basic chemicals or mineral nutrients in the soil.
New Life
•
New plants then start to grow.
•
They use energy from the sun, water from the soil, and gases in the air to make
their food.
•
These plants use the chemicals or mineral nutrients from the soil to grow healthily.
•
This is how the nutrient cycle repeats itself.
The Nutrient Cycle
Elements in the Air
•
Carbon dioxide and oxygen are cycled on Earth through plants and animals.
•
Animals need oxygen to survive.
•
They breathe in oxygen from the air, and they breathe out carbon dioxide.
•
Plants need carbon dioxide from the air, and they give off oxygen as waste.
•
This oxygen is then breathed in by animals.
Oxygen
•
Plants make almost all the oxygen found in the atmosphere.
•
Like most living things, plants use oxygen to live.
•
Fortunately, plants make much more oxygen than they can use.
•
This leaves plenty of oxygen for animals to use.
Photosynthesis
•
The process of making food in green plants is called photosynthesis.
•
The word comes from two different words:
•
•
“Photo” means light
“Synthesis” means putting things together
•
Photosynthesis uses carbon dioxide, water and light energy to make food.
•
The process of photosynthesis can be shown as the following equation:
Photosynthesis
•
Photosynthesis takes place in the green parts of the plant.
•
This is in the leaves of most plants.
•
The light energy that is used in photosynthesis comes from the sun.
•
It is captured by the chloroplasts in the cells of the leaves.
Leaves
•
The leaves also take in carbon dioxide.
•
This comes from the air.
•
Most leaves have tiny openings on their undersides called stomata.
•
These openings allow air to enter the leaf.
•
The leaf uses the carbon dioxide from the air to make the sugar and starches.
•
The oxygen made is released into the air through the stomata.
Water
•
The water needed comes from the ground.
•
The roots of plants take in water and dissolved chemicals from the ground.
•
The water moves from the roots up through the stem to the leaves of the plant.
•
The substances are then changed into food and oxygen.
Photosynthesis
The Water Cycle
•
The water cycle plays an important part in the survival of living things.
•
For example, plants take in water through their roots.
•
The water is transported up through the stem to the leaves.
•
The water is used by the leaves during photosynthesis.
•
The stomata, found on the underside of the leaves, releases water vapour.
•
This is called transpiration.
Transpiration
Leaves
•
Broad leaves have greater surface area than needle leaves.
•
There are more stomata found in a broad leaf, so more moisture is lost during
photosynthesis.
•
Broadleaved trees transpire a lot of moisture into the air.
•
On a warm, sunny day, a fully grown tree may release as much as 450L of moisture
into the air through transpiration.
•
In a forest, this moisture has a cooling effect like an air conditioner has on a house.
Seasonal Changes
•
The days get colder and drier in autumn and winter.
•
If the leaves were allowed to remain on the tree, too much moisture would be lost,
or the leaves would freeze.
•
To prevent this from happening, the tree drops, or sheds, its leaves.
Needle-Leaved Trees
•
Most needle-leaved trees are evergreen.
•
They are able to keep their leaves because of their shape and size.
•
Being smaller, needle leaves have much fewer stomata than broad leaves.
•
Therefore, they transpire less.
•
The tree is able to keep the needle leaves during the dry and cold months.
•
Needle leaves are shed gradually throughout the year.
Which of the following trees will release the
most moisture into the atmosphere through
transpiration?
A
B
C
D
Use the following information to answer
the next question.
•
Patrick saw this illustration in a science book.
What process is illustrated in the given
picture?
A.
Respiration
B.
Photosynthesis
C.
The water cycle
D.
The nitrogen cycle
Hope concluded her presentation by
explaining that the most important benefit
trees and forests have is found everywhere on
Earth but cannot be credited to a specific
area.
The most important of trees that Hope was
referring to is that trees provide:
A.
Food for everyone
B.
Oxygen for everyone
C.
Jobs for many people
D.
Homes for many animals
Producers, consumers and decomposers
are linked in what is known as the
A.
Animal cycle
B.
Energy cycle
C.
Nutrient cycle
D.
Chemical cycle
Leaves produce food for trees by the
process of
A.
Transpiration
B.
Respiration
C.
Digestion
D.
photosynthesis
As a tree decays, it will
A.
Add nutrients to the soil
B.
Add oxygen to the soil
C.
Remove nitrogen from the air
D.
Remove water from the air
In a process called photosynthesis, trees use
the energy from the sun to make their own
food supply. During this process, trees release
A.
Water vapour and take in oxygen
B.
Oxygen and take in water vapour
C.
Carbon dioxide and take in oxygen
D.
Oxygen and take in carbon dioxide
IDENTIFY GENERAL
CHARACTERISTICS THAT
DISTINGUISH TREES FROM
OTHER PLANTS, AND
CHARACTERISTICS THAT
DISTINGUISH DECIDUOUS
TREES FROM CONIFEROUS
TREES
Parts of a Tree
•
Most trees have the same basic parts
•
•
•
•
•
•
•
•
•
Roots
Trunk or stem
Crown
Outer Bark
Inner Bark (Phloem)
Cambium
Sapwood (Xylem)
Heartwood
Leaves
Roots
•
A tree’s roots absorb water and nutrients from the soil, store sugar and anchor the
tree upright in the ground.
Trunk or Stem
•
The trunk or stem supports the crown and gives the tree its shape and strength.
•
The trunk is made up of tubes that run between the roots and the leaves.
•
Some tubes carry the food down from the leaves to the other parts of the tree.
•
Other tubes carry water and dissolved mineral nutrients from the soil to the
leaves.
Crown
•
The crown consists of the leaves and the branches at the top of the tree.
•
The leaves are the food factories for the tree.
•
The leaves contain the green pigment chlorophyll that traps the energy of the sun
used for photosynthesis.
Bark
•
The bark consists of two parts:
•
•
The outer bark
The inner bark
Outer Bark
•
Acts like a suit of armour for the tree.
•
Protects the tree from insects, disease, storms and extreme temperatures.
Inner Bark
•
Also called phloem
•
Acts as a food supply line by carrying sugar and nutrients (sap) from the leaves to
the rest of the tree.
Cambium
•
Between the outer bark and the inner bark
•
Very thin layer of growing tissue that produces new cells that become xylem,
phloem or more cambium.
Xylem and Heartwood
•
Also called sapwood
•
Has a network of thick-walled cells that bring water and nutrients up from the
roots to the leaves and other parts of the tree.
•
As the tree grows, xylem cells become inactive and die.
•
These cells become the tree’s heartwood.
•
Heartwood supports the tree and stores the dead xylem cells.
•
The heartwood also stores sugar, dyes and oils.
Stems
•
Both trees and shrubs have woody stems
•
This sets them apart from other plants
•
A sunflower can grow fairly tall but because it does not have a woody stem, it is
not considered to be a tree or shrub.
Differences Between Trees and Shrubs
•
A tree is a perennial plant meaning it continues to grow year after year.
•
It does not die off after one growing season as many plants do.
•
Trees generally have a single, woody stem called a trunk that is self-supporting.
•
Trees grow to a height of 4m or more.
•
Trees have a crown of leaves at the top that give it its shape
•
A shrub is also a perennial plant.
•
Instead of a single stem, it has many woody stems
•
Shrubs usually do not grow more than 4m in height, and some stems may lie close
to the ground.
Deciduous and Coniferous Trees
•
Trees can be categorized into two types:
•
•
Deciduous
Coniferous
Coniferous Trees
•
Have needle-shaped leaves
•
Are cone-bearing
•
Most remain green all year long and as such, are referred to as evergreens.
•
Evergreens lose their needles gradually over the year rather than all at once in
autumn.
•
Much less moisture is lost from a needle leaf than through a broad leaf.
•
There are various shapes of coniferous trees.
Deciduous Trees
•
Shed their leaves before the cold or dry season.
•
Before shedding, the leaves often turn orange, red or yellow.
•
New leaves appear in the spring.
•
Most have wide-shaped leaves and are often called broadleaved trees.
•
There are many different varieties and sizes
Which of the following statements about
deciduous trees and coniferous trees is false?
A.
Both deciduous and coniferous trees have seeds.
B.
Both deciduous and coniferous trees have leaves.
C.
Deciduous and coniferous trees both have flowers.
D.
Deciduous and coniferous trees both have woody stems.
A plant is classified as a tree if it has
A.
A woody stem
B.
Leaves or needles
C.
Leaves that change colour
D.
Roots that reach 3m in length
IDENTIFY CHARACTERISTICS OF AT
LEAST FOUR TREES FOUND IN THE
LOCAL ENVIRONMENT. BE FAMILIAR
WITH AT LEAST TWO DECIDUOUS
TREES AND TWO CONIFEROUS TREES.
INCLUDE NATIVE SPECIES, SUCH AS
SPRUCE, BIRCH, POPLAR AND PINE
AND CULTIVATED SPECIES, SUCH AS
ELM AND CRAB APPLE.
Native and Cultivated Trees in Alberta
•
A native tree is one that naturally grows in the area.
•
There are many different native trees found in Alberta.
•
The types of trees found in your area depend on where you live.
White Birch
•
Small- to medium-sized tree with many stems.
•
The bark is thin, smooth and marked with brown horizontal lines.
•
The bark is light, strong and flexible.
•
It peels off in paper strips.
•
Birch trees in the forest have a narrow, oval-shaped crown above a slender trunk.
•
The leaves have a simple, round shape with a fine-toothed margin.
•
White birch trees are not cone-bearing trees.
•
In the past, Aboriginal Peoples used birch bark to build canoes.
Poplar
•
Very common in Canada
•
Used for making paper and makes excellent firewood
•
The poplar tree has oval-shaped leaves that have a fine-toothed margin.
•
The bark is smooth and yellowish.
•
In the past, poplar trees played an important role in natural medicine.
•
There are two main types of poplar trees:
•
•
Aspen poplar
Balsam poplar
Aspen Poplar
•
Sometimes called a white poplar, trembling aspen, white cottonwood, quivering
aspen, or quaking aspen.
•
The leaves shake or flutter in the breeze, which is why it is called a trembling or
quivering aspen.
•
The aspen poplar is a slender tree with smooth, greenish-white bark that does not
peel away.
•
The seeds are found in green capsules containing clumps of cottony fluff.
•
The aspen poplar can sprout from root suckers as well as from seeds.
•
The leaves are simple and heart-shaped, with long, flat stalks.
•
The upper surface of the leaf is dark green, and the underside is paler green.
•
The margins on the leaves are fine-toothed.
Balsam Poplar
•
Sometimes called the black poplar.
•
Have straight trunks with bark that is greenish grey when young and brown with
grooves when old.
•
The tree produces buds that contain a sticky substance that has a pleasant balsam
smell.
•
The leaves are simple and oval- or wedge-shaped with fine-toothed margins.
•
The upper surface of the leaf is dark green, and the underside is paler with rustcoloured marks.
Spruce Trees
•
Large trees with narrow crowns
•
Coniferous, or cone-bearing
•
Cones are light brown and scaly
•
Have needles
•
Needles are four-sided, stiff and sharp
•
Needles are arranged spirally on a twig
•
The bark of a spruce tree is scaly and greyish brown
•
Most common wood used for building in Canada
White Spruce
•
Found in all forest regions in Alberta
•
Some of the first coniferous trees to start growing in burned-out pine and old
aspen poplar forests.
Black Spruce
•
Found in all forested areas, especially in northern parts of Canada
•
One of the few conifers that grows well in wetland areas such as bogs and muskeg
Pine Tree
•
Most widespread tree in Canada
•
Cone-bearing
•
Have needles that appear in pairs
•
Bark is thin and scaly
•
Most commonly used for plywood, panelling, furniture and railway ties
•
Most common trees used by Aboriginal Peoples to build teepees
•
First trees to grow back after a forest fire
Jack Pine
•
Grows in areas with sandy soil
•
Common tree in the Boreal Forest
Lodgepole Pine
•
Tall, slim tree that grows to 30m or more
•
Used as the poles for powerlines, lodges and buildings, which is why it is called the
lodgepole pine
•
Common tree in the Rocky Mountain and Foothills area
•
This is the provincial tree of Alberta
Cultivated Tree
•
A cultivated tree is a tree that did not grow in the area naturally.
•
Although these trees were brought from other places, they adapted to the new
region and began to thrive.
•
Two of the many cultivated trees are:
•
•
Elm
Crab apple
Elm Tree
•
A deciduous broad-leaved tree
•
These shade trees grow well in many different soils
•
The elm leaf has an elliptical shape with serrated margins
•
The leaves do not grow opposite each other on a branch; they are staggered
•
Manu streets in Edmonton and Calgary are lined with elm trees
•
Precautions have been taken to prevent elm populations from Dutch elm disease.
Crab Apple
•
Deciduous broad-leaved tree
•
May have white or pink flowers on a small, multi-stemmed tree
•
Apples can be harvested in late summer or early autumn.
•
The crab apple leaf is dark green and oval- to egg-shaped with a finely notched
margin.
Which of the following trees has hard
cones that open when exposed to heat?
A.
Jack pine
B.
White birch
C.
Aspen poplar
D.
White spruce
Which of the following Albertan trees is
deciduous?
A.
White spruce
B.
Jack pine
C.
Birch
D.
fir
Which of the following trees is a deciduous
tree that does not tolerate shade and is used
to make paper?
A.
Elm
B.
Spruce
C.
Poplar
D.
Jack pine
New growth on trees can best be seen in
the spring by looking at a tree’s
A.
Terminal growth or end bud
B.
Annual growth ring
C.
Leaf scar
D.
lenitcel
DESCRIBE AND CLASSIFY
LEAF SHAPES, LEAF
ARRANGEMENTS,
BRANCHING PATTERNS AND
THE OVERALL FORM OF A
TREE
Classifying Leaves, Branching Patterns
and Tree Shapes
•
The features of different species of trees’ leaves, bark, twigs, buds, flowers and
fruits are distinctive.
•
You can identify trees by their shape or silhouette.
•
For some species, a particular feature stands out.
•
For example, the white birch has a distinctive bark, and the black spruce has an
easily recognizable shape.
Leaves
•
Leaves are the most common feature considered when identifying a tree.
•
The leaf itself is called the blade.
•
The stem of the leaf is the petiole.
•
The tip of the leaf is the apex.
•
The edge of the leaf is the margin.
•
The vein in the middle of the leaf is called the midrib or midvein.
•
The branches coming out from the midvein are the veins.
Factors in Leaf Identification
•
Important factors in leaf identification:
•
•
•
•
Shape of a leaf
Kind of leaf margin
Leaf type
Arrangement of leaves on the twig
Leaf Shapes
•
There are 10 different leaf shapes:
•
•
•
•
•
•
•
•
•
•
Linear
Oblong
Oval
Ovate
Cordate (heart-shaped)
Lobed
Deltoid (triangular)
Orbicular (round)
Four-sided needles
Flat needles
Linear
Oblong
Oval
Ovate
Cordate (Heart-Shaped)
Lobed
Deltoid (Triangular)
Orbicular
Four-Sided Needles
Flat Needles
Margins
•
Leaves can also be classified by their margins
•
Leaf edges, or margins can be:
•
•
•
•
Smooth
Finely notched
Coarsely notched
Wavy
Smooth
Finely Notched
Coarsely Notched
Wavy
Shape
•
Another way to classify leaves is by shape.
•
•
•
Simple
compound
Double compound
Simple
•
there is only one leaf on each petiole.
Compound
•
there is more than one blade on each petiole
Double Compound
•
there are several blades attached to several petioles
Arrangement
•
Leaves can also be classified by their arrangement on a twig.
•
•
•
•
•
Opposite
Alternate
Whorl
Basal
Needle arrangements can be:
•
•
•
•
In bundles of 2 and 5
Singly on a twig
Scalelike
In clusters of more than 5
Bark
•
Tree bark can be differentiated according to:
Colour
• Texture
• Bark patterns
•
•
The bark of most trees changes colour and thickens as the tree ages.
•
Bark can be reddish brown, grey or white.
•
Texture of bark can be smooth or rough.
•
Bark patterns include:
•
•
•
•
•
Scaly patches
Horizontal
Vertical
Horizontal and wavy
Vertical and scaly
Bark Patterns
Grey, rough, vertical
Grey, rough,
scaly patches
Reddish-brown,
smooth,
horizontal
White, smooth,
horizontal
Overall Shape
•
The overall shape or silhouette of a tree may also be used to differentiate between
tree species.
•
Trees can have the following shapes:
•
•
•
•
•
Triangle or cone
Oval
Circle
Spreading
Rectangular
•
Most trees are easily identified by their shape or silhouette.
•
For example, a fir tree is easily identified by its triangular shape.
Tree Shapes
Triangular or
cone
Circle
Oval
Spreading
Rectangular
Branch Patterns
•
Typically, trees develop different branch patterns.
•
Branching patterns on trees can be arranged in a whorled, opposite, alternate or spiral
arrangement.
•
Branches can also be arranged in relation to the trunk.
•
Sometimes, trees have excurrent branches, which means the tree’s branches go all the
way up the trunk.
•
For some trees, the branches only begin halfway up the trunk.
•
If the trunk is split to form two or three main branches, it forms a decurrent pattern.
•
A columnar pattern is one where the branches are all clustered at the top of the trunk.
•
Palm trees have a columnar branch pattern.
Branch Patterns
Columnar
Decurrent
excurrent
Factors Affecting the Shape of a Tree
•
The shape of a tree is dependent on many factors
•
•
•
•
Relative amount of growth of the trunk
Branches
Site condition
If the tree is in an area where there is a lot of wind or it is growing on a slope, the
tree’s shape or branching pattern may be changed by these conditions.
Using a Dichotomous Key
Which of the following trees were used by
Aboriginal Peoples to make canoes?
A.
Pine
B.
Birch
C.
Poplar
D.
Spruce
The lodgepole pine, Alberta’s official tree, was
named by the first European settlers. They
chose this name because it describes the way
in which the tree was used by
A.
Settlers to make fences
B.
Settlers to make flagpoles
C.
Aboriginal Peoples to make canoes and other boats
D.
Aboriginal Peoples to make frames for their bison-skin homes
INTERPRET THE GROWTH PATTERN OF
A YOUNG TREE, DISTINGUISHING THIS
YEAR’S GROWTH FROM THAT OF THE
PREVIOUS YEAR AND FROM THE YEAR
BEFORE THAT. RECOGNIZE
DIFFERENCES IN COLOURATION AND
TEXTURE OF NEW GROWTH AND OLD
GROWTH, AND LOCATE SCARS THAT
SEPARATE OLD AND NEW GROWTH
Growth Pattern of Trees
•
Foresters study tree cross sections, or discs, which are sometimes called tree
cookies, in order to learn about the pasts of individual trees.
•
The study of trees can tell people things about the history of the area surrounding
the tree.
•
For example, a scar can show that there was a fire, or the last drought in the area
may result in a very narrow growth ring.
•
The study of tree discs is called dendrochronology.
Growth Rings
•
Trees form new wood in the spring and summer only.
•
Springwood is lighter in colour than summerwood.
•
This growth shows up in a series of light (spring growth) and dark (summer
growth) rings called annual rings.
•
Growth rings vary in size according to each year’s growing season.
•
Environmental conditions, such as weather, the amount of growing space, soil
conditions, insect attacks, and fire influence their size.
•
The study of growth rings can tell people a lot about a tree’s history.
•
The centre of the ring indicates the birth of the tree.
•
An evenly spaced ring indicates rapid growth.
•
Rings wider on one side than the other indicate that it was growing on a slope, or
that something may have been leaning against it, forcing the growth to one side.
Narrow Rings, Fire Damage and Scars
•
Narrow rings could indicate either overpopulation or a lack of water.
•
Several narrow rings indicate a series of drought seasons.
•
A dark, black area with the rings growing in toward the black area indicates
possible fire damage.
•
Sometimes, a scar is left where a branch breaks off or dies.
•
The scar goes around several years of growth as the tree tries to build new growth
rings around it.
•
This scar is different from a fire scar, which occurs only in one year.
Identifying Age of Trees
•
Another way of identifying the approximate age of trees is by counting the
number of terminal bud-scale scars on a broad-leaved tree branch or by counting
the number of whorls on an evergreen.
Bud
•
A bud is the bump found on branches and twigs of a tree.
•
It can become a leaf, a flower or stem material that will begin to grow in the next
spring.
•
Buds form in the late summer and remain dormant until the following spring.
•
When the bud opens, the scales usually fall off.
•
The scales leave little tiny grooves or scars where they were attached.
•
Each year, as the branch grows, a set of scars is left behind.
•
You can determine the age of a branch by counting these scars.
Terminal Bud Scars
•
Terminal bud scars show the growth of a branch.
•
This method of determining the age of a tree is unreliable.
•
As the branch grows, it becomes thicker.
•
Since the scars cannot stretch around the tree, they disappear.
Whorls
•
The branches of some evergreens, such as the white spruce, are arranged in
groups of whorls around the trunk of a tree.
•
The number of whorls can give the age of the tree.
•
This method of determining the age of a tree is unreliable because as the
evergreen tree ages, branches can break or die off.
Insect Attacks
•
An area of one or two narrow rings may indicate an insect attack.
•
In the years of insect attacks, the leaves of the tree would be damaged and very
little food would be made that year.
Sorida and her father are studying the tree cookie shown.
Sorida wants to know how old the tree was when it was
cut. Her father says that they can find out the age of the
tree by examining the tree cookie.
To determine the age of the tree when cut, Sorida and her
father can count
A.
All the dark rings, including the bark
B.
All the dark rings, excluding the bark
C.
All the dark and light rings, including the bark
D.
The dark and light rings, excluding the bark
Which of the following statements about
tree rings is true?
A.
A thin ring indicates that the tree grew more that particular year than in other
years.
B.
A thick ring indicates that the tree grew more that particular year than in other
years.
C.
An unusually dark ring indicates that the tree probably suffered from a disease
that particular year.
D.
An unusually light ring indicates that the tree probably suffered from too much
sunshine that particular year.
The four parts of a tree’s life cycle are as
follows:
A seed germinates.
2. First roots and leaves form.
3. The mature tree produces flowers.
4. The trunk adds a ring of growth every year.
•
List in the order in which they occur, the four parts of a tree’s life cycle are: _____,
_____, _____, and ______.
IDENTIFY HUMAN USES OF
FORESTS, AND COMPARE
MODERN AND HISTORICAL
PATTERNS OF USE
Past and Present Use of Forests
•
Humans began life on the planet as forest dwellers
•
They were food gatherers and depended on the forest for all their needs
•
•
•
Food
Clothing
Shelter
•
Humans gradually became food growers, clearing small patches in the forest to
grow food.
•
But they continued to depend on forests to meet a lot of their needs.
Modern Uses for Forests
•
Even today, people depend on forests for
•
•
•
•
•
Paper
Timber
Fuel wood
Medicine
Trees are used in timber-based products such as
•
•
•
•
Plywood
Paper
Pulp
particleboard
Medicinal Uses
•
Humans have depended on forest herbs and plants to fight and prevent various
ailments
•
Today, leaves, bark and other parts of trees have medicinal values and are used to
make various medicines.
Use the following information to answer
the next two questions
Taxol is a chemical found in the bark of the Pacific yew tree. Taxol is a chemical that
is sometimes used in drugs that fight cancer. The entire bark of one Pacific yew tree
contains enough Taxol to make one pill. A fungus that grows inside the Pacific yew
tree also produces Taxol. The fungus helps protect the tree from disease and
predators. However, if the soil becomes very dry, the fungus becomes a disease of
the Pacific yew trees. Logging by lumber companies is affecting the Pacific yew
trees’ habitat. As more trees are cut down, more of the ground is exposed to the sun
and wind. This tends to make the soil very dry.
Which of the following conclusions can best
be made from the given information?
A.
Trees are sources of medicine
B.
Trees that have fungus are generally healthy.
C.
More research about trees is needed to find useful chemicals in them.
D.
More research about trees is needed before humans alter their environment.
A useful goal of researchers would be to
try to:
A.
Learn how to identify the Pacific yew tree
B.
Grow the Taxol-producing fungus in a lab
C.
Find better ways to remove the yew bark
D.
Grow Pacific yew trees in Alberta
Use the following information to answer
the next two questions.
Liam was researching the historical and modern uses of forests. By comparing
forest use in the seventeenth century with forest use in the twenty-first century,
Liam found many things that had changed. He noted that forest use for shelters,
leisure and jobs had increased over time, while forest use for fuel and transportation
had decreased.
Liam discovered that the main reason that
forest use for shelters had increased is that
A.
More people need homes today
B.
People live in smaller homes today than they did in the past
C.
Log cabins have become more popular in the twenty-first century
D.
Many of today’s campers know how to use temporary shelters made from trees
Liam inferred that the main reason that forest
use for fuel and transportation had decreased
is that
A.
There are fewer demands for fuel and transportation needs today
B.
Better materials are now used to meet fuel and transportation demands
C.
Conservationists have banned the use of forests for these types of needs
D.
Clear cutting has reduced forests, thereby reducing what they can be used for
IDENTIFY HUMAN ACTIONS
THAT ENHANCE OR
THREATEN THE EXISTENCE
OF FORESTS
Actions That Enhance or Threaten Forests
•
Biotic stress is stress resulting from the harmful actions of a living organism, such
as insect attacks, disease-causing fungi and overgrazing of animals such as deer
and cattle.
•
Abiotic stress is stress resulting from natural factors that are not alive.
•
•
These factors include snow, ice, fire and wind.
Drought, extremes of heat and cold, and pollution are three abiotic stresses that have
played parts in the decline of forests.
Natural Factors
•
Sometimes, natural factors can have both a negative and a positive effect on
forests.
•
For example, snow and ice break tree branches and can cause flooding leading to
soil erosion.
•
On the positive side, snow and ice provide moisture for the soil needed for trees to
grow.
Humans Threaten Forests
•
Humans have threatened forests by the following actions:
•
•
•
•
•
•
•
Overlogging in an area
Careless use of fire
Overuse of recreation areas such as lakes found in forests
Use of pesticides
Building roads
Littering and polluting
Clearing forests for farms or new housing developments
Forestry
•
Alberta’s forest industry has provided the province with a major source of
economic growth over the past 30 years.
•
Reforestation is one way that industry works to ensure forests are maintained.
•
Reforestation requires that the forest industry either plants seeds for new trees to
grow, or they plant small trees that have been grown in nurseries.
Government Programs
•
Other ways forests have been enhanced and preserved is through government
programs.
•
These programs enhance and preserve forests by the following actions:
•
•
•
•
Establishing provincial and federal parks
Setting up wilderness protection sites and animal sanctuaries
Hiring forest managers and park rangers to monitor and police forested areas
Enhancing recreation areas by restocking lakes or planting trees for campsites
Which of the following statements indicates
that Canadians are taking action to enhance
forests?
A.
Forestry industries employ over 800 000 Canadians
B.
Over 350 communities have economies that depend on forests
C.
Hundreds of clear cutting projects are carried out today in all provinces of
Canada.
D.
Millions of hectares of forests in Canada are protected by law so they can
remain in their natural states.
IDENTIFY AN ISSUE
REGARDING FOREST USE,
IDENTIFY DIFFERENT
PERSPECTIVES ON THAT
ISSUE, AND IDENTIFY
ACTIONS THAT MIGHT BE
TAKEN
Forest Issues and Actions
•
Forests are affected by a number of interacting stresses.
•
Most people agree that forest ecosystems are suffering from a combination of
natural stresses and man-made stresses.
•
Air pollution, harvesting, fire and overuse by humans are some examples of things
that threaten forests.
•
The management and preservation of today’s forests continues to be an issue in
Alberta’s forest industry.
Acid Rain
•
Serious damage to forests can also result from acid rain.
•
Acid rain is formed when rain falls through polluted air.
•
Acid rain kills leaves and trees.
•
It can cause permanent damage to the soil of the forest floor, which, in turn, kills
tree roots.
Clear Cutting
•
Clear cutting of Alberta’s forests has detrimental effects on the entire ecosystem
of the forest.
•
Clear cutting requires the use of large machinery that cuts down entire sections of
the forest.
•
This exposes soil, which then erodes.
Selective Harvesting
•
Instead of clear cutting, a much preferred method of harvesting trees is selective
harvesting.
•
This is where only the largest trees are chosen, and smaller trees are planted to
replace them.
Which of the following actions would help
to preserve or enhance a forest?
A.
Increase hunting activities
B.
Clear more land for campsites
C.
Plant seedlings in a previously harvested area
D.
Spray insecticides on trees infected with pine beetles
Use the following information to answer
the next two questions
•
Clear cutting: Large machines cut the trees, remove the branches, cut the logs
into eight-foot lengths and load them onto large trucks, all at one spot. The size of
the machines allows the company to cut all the trees in the area. Smaller plants
often get run over, and the soil is compacted by the tires of the heavy machinery.
•
Selective cutting: This is a small-scale operation. One or two operators cut trees
with a chain saw on the property they own. They select the largest trees to cut,
allowing space for the smaller trees to grow. A horse may be used to drag the logs
out of the bush because vehicles are usually too large.
•
Strip cutting: Heavy machinery is used but the trees are cut in strips, leaving
sections between the strips uncut. From the air, the land looks like zebra stripes.
This limits the effect of wind erosion. As well, strips of vegetation are left along
lakes and rivers to reduce soil erosion into the water.
In order of the least harmful to the
environment to the most harmful to the
environment, these techniques are:
A.
Selective cutting, strip cutting and clear cutting
B.
Clear cutting, strip cutting and selective cutting
C.
Strip cutting, selective cutting and clear cutting
D.
Strip cutting, clear cutting and selective cutting
In order of the fastest way to cut trees to the
slowest way to cut trees, these techniques
are:
A.
Selective cutting, strip cutting and clear cutting
B.
Clear cutting, strip cutting and selective cutting
C.
Strip cutting, selective cutting and clear cutting
D.
Strip cutting, clear cutting and selective cutting
A small logging company employs one or two
operators to cut trees with a chain saw. They select
large trees, allowing smaller trees more space in
which to grow. A horse may be used to drag the
logs out of the bush because vehicles are too big to
manoeuver through the forest.
This logging technique is known as
A.
Strip cutting
B.
Clear cutting
C.
Natural logging
D.
Selective cutting