Trees and Forests

Forest Ecosystems Habitat: an environment where

something lives Ecosystem: a living community

that depends on each member and it’s surrounding environment (cooperating together to survive)

Living things in the forest: Producers – living things

that use energy from the sun to produce their food.

Consumers - living things that eat the producers Three types of consumers

– herbivores, carnivores and omnivores

Decomposers – living things which feed off dead plants and animals They reduce the remains to

nutrients and minerals for the soil

Examples – mushrooms (fungi) and bacteria

Non-living things in the forest – water, rocks, sunlight, air, soil and chemicals.

*Forests serve as habitat for a variety of living things *

In groups, discuss what makes up a forest ecosystem and list the living and non-living things in a chart like the one below. (Please complete in your Science duo-tang:

Then, create a web identifying why trees and

forests are important. Include images to correspond with your ideas. (Blank paper will be provided for this.)

Living things (biotic)

Non-living things (abiotic)

Did you come up with the same things?

Living things (biotic)

Non-living things (abiotic)

• Plants • Algae • Animals • Fungus • Bacteria • Trees

• Water • Air • Soil • Dead organisms • Rocks

Importance of Trees & Forests

Importance of Trees

and Forests

Air: Produce O2

Absorb CO2

Controls Erosion

Soil: Enrich the soil with

decaying leaves etc.

Homes and Shelter for people and

animals

Recreational Activities

People: Shade &

wind protection

Food: nuts, fruit, oil

Resource: Wood

The Importance of Trees and Forests

To Nature home for animals, insects, plants

and other organisms production of oxygen preservation of other eco-systems Medicinal Purposes Many forests contain natural

remedies which are used to help develop modern medicines and cures for many ailments

For Recreation green space for hiking camping hunting For Corporations wood for building jobs for locals paper production

Organisms and Trees Sharing a Home Before watching this film, read over the following questions which will be used to write a journal entry.

1. What are 3 new things you learned about trees and forests from this video?

2. Name 5 animals that rely on the ecosystem of the forests to survive and how do they use this ecosystem to live. They cannot all be animals; you must have 1 animal, 2 plants, 1 insect and 1 other organism.

3. If you were a biologist, what would you like to study about trees and forests and why does this topic interest you so much?

Nutrient Cycle of Trees Just like people, trees need

food to survive. Everything they need to be healthy comes from sunlight, water, air and soil.

Leaves contain a chemical called chlorophyll. Through photosynthesis, then chlorophyll turns sunlight into food.

Using the energy from the sun, the leaves change carbon dioxide and water into starches and sugar. These two substances then help the tree to continue to grow and maintain life functions.

Nutrient Cycle

Producers: Get nutrients from the

soil

Consumers: Get nutrients from plants

and animals

Decomposers: Get nutrients from dead plants and animal

material. Nutrients, then returned to the

soil.

Levels of a Forest There are four Forest Layers

Upper canopy: top layer of the forest Captures more than 90% of the

sunlight Where most of the photosynthesis

occurs A Lot of flying animals can be found

here. Humming bird, owl, and

insects(butterfly, caterpillars). Understory: Many small trees, larger

bushes and shrubs. Provides shelter for many forest

animals Shrubbery layer: Home to many

forest wildflowers, ferns, deer skunks and rabbits These animals find their food on

this level.

Forest Floor: Dark and damp. Only plants that can live with very little light grow here.

Fungi decompose dead plant material here

Fungi are not green because they don’t have chlorophyll and can not produce food through photosynthesis.

Fungi eat dead plant material. Mushrooms, conks and lichens are examples of fungi.

Decomposers such as worms, bacteria, millipedes, and centipedes are examples of decomposers.

Inhabitants of the forest floor are toads, mushrooms, and insects.

Who lives in the forests?

Fungi: white and brown but never green; most fungi feed on dead trees, a few on living trees.

Lichens: are two plants, a fungus and an alga, that live together in symbiosis (help each other); are grey, green or orange; use the tree only for support; they look like splotches of paint.

Mosses: are green, even all winter; like the cool moist bases of tree trunks, as well as fallen dead trees; use the tree just for support.

Animals: include woodpeckers, squirrels, owls; many of them use trees for their homes and for their food supplies.

How do trees effect a forest? They break the wind and

with less air movement, there is less drying.

They shade the ground from the sun thereby lowering air temperature; forests tend to be cool, humid places and the soil is moist there.

Forest soil is also very rich in nutrient because of all the leaves, branches, and stems which decompose into humus (soil).

Food Chains A food chain is a sequence of organisms in an ecological community, each of which is food for the next higher organism from the primary producer to the top predator or carnivore.

Primary consumer: first consumer to eat the producer

Secondary consumer: a consumer which eats the first consumer

Tertiary consumer: a consumer which eats the second consumer

* Create a table as shown below and research different types of consumers that fit into each category.

Primary Consumer

Secondary Consumer

Tertiary Consumer

What is a tree? A tree is defined according to the following

criteria: It must be perennial (lasting for more than

2 growing seasons) It must have a self supporting trunk A tree usually grows to a height of 5 to 7

metres NOTE: a young tree that has not yet

reached adult height is called a sapling.

Trees are the largest of all plants. The tallest trees grow higher than 30-story buildings.

Many trees also live longer than other plants. Some live for hundreds or even thousands of years.

They are the oldest known living things.

Trees continue to grow as long as they live.

Each year a new layer of wood is added to the trunk of the tree.

Trees rest during the winter months. Trees in this state are called dormant.

Click to check

out the World’s Oldest Trees.

Parts of a Tree Root Anchor the tree to the earth supply the tree with nutrients and

water Leaf makes sugar from the air and

water Branches support the leaves, holding them

up to get sun light Crown the upper part of a tree made up

of branches, twigs, leaves, needles, buds and cones

Trunk strongest part of the tree providing

support for the rest of the tree Outer Bark (cork) outer part of the trunk; is dead

tissue; protects the living parts underneath.

Xylem • hollow cells that transport water

and minerals from the roots throughout the tree make up the wood of the tree.

Parts of a Tree: TRUNK Outer bark protects the tree from fire and

insects

insulates the tree from extreme temperatures

Phloem a pipeline which carries

nutrients from the leaves to the rest of the tree. These cells eventually die and become a part of the tree

Cambium this is where the growth of the

tree is

cambium produces new phloem and sapwood

produces the annual rings to tell the age of a tree

oldest part of the tree is always on the inside

Sapwood carries the nutrients from the

roots to the leaves

As these layers die, they become heartwood

Heartwood the dead wood at the center of

a tree

gives a tree its strength

Parts of a Tree

Leaves •flat like structures containing most of the chlorophyll and are the main sites of photosynthesis. Use sunlight, water and carbon dioxide to produce food for the trees and free oxygen gas.

Needles •needle-like structures containing most of the chlorophyll and are the main sites of photosynthesis. Use sunlight, water and carbon dioxide to produce food for the trees and free oxygen gas.

Cones •small woody structures which produce seeds on coniferous trees

Plants vs. Trees All other plants differ from trees in at least one of these ways:

No plant with a soft, juicy stem is a tree.

Most plants are much shorter than trees.

Shrubs, like trees, have woody stems; but most shrubs have more than one stem, none of the stems grow so thick as to be called a trunk.

Some jungle vines grow several hundred meters long and have a woody stem. However, the stems of vines cannot support themselves.

Complete the T-Chart

Tree Plant

Complete the T-Chart

Tree Plant • Perennial • Perennial, annual,

biennial

• Trunk • Stem

• Woody material • Woody or non-woody material

• Leaves or needles • Leaves

• Flowers, fruit, seeds

• Flowers, fruit, seeds

Production of Oxygen Photosynthesis Without trees, we

would not have the oxygen we have today. In order for trees to get nutrients, it uses sunlight as an energy source to convert carbon dioxide from the air into sugars. Theses sugars feed the plant essential nutrients resulting in a chemical reaction where oxygen is given off.

Leaves make food from water and carbon dioxide

Sunlight captured by chlorophyll traps light energy. Chlorophyll is what makes the leaves green.

Chlorophyll molecules use light energy to change carbon dioxide and water into oxygen, sugars, and starches.

Leaves release the oxygen they don’t need into the air and keep the sugar for food.

Plants give off almost all the free oxygen in the atmosphere.

Life of a Tree

Dendrochronology: the scientific study of growth patterns and the aging of trees as shown in their rings.

Dendrodisc: tree cookie; a cross-sectional slice of a tree.

Easily visible rings can provide information about the weather, soil,and light conditions over time.

Rings on a tree are the result of rapid growth in the spring (called springwood), and slower growth in the summer and fall (summerwood). The dark ring is the summerwood and the lighter coloured ring is the springwood. Together, these represent one year of growth or an annual ring. There is little to no growth during the winter months.

How Trunks and Branches Grow Thicker

The trunk and branches of broad leaf and needle leaf trees grow thicker as long as the tree lives.

The cambium tissue just underneath the inner bark causes this thickening; it used the sugar manufactured by the leaves to make new plant tissue.

On the outside, the cambium makes new phloem tissue or inner bark; on its inside, it makes new xylem tissue or sapwood.

How Trunks and Branches Grow Thicker

The growth rings of very old trees can tell us much about the weather conditions in long-ago times.

In periods of great drought, the rings do not grow as thick as in seasons when rainfall is plentiful.

From that fact, scientific historians can piece together many secrets of the long-dead past.

Why do leaves fall? Historically, it was thought

that the drop in temperature during autumn caused leaves to wither and fall.

Scientists discovered that the falling of leaves was related to light.

The shorter periods of daylight affect a special layer of cells at the base of each leaf where it joins the twig from which it grows.

In the fall, as the days grow shorter, this cell layer weakens and the leaf turns brown and drops off the tree.

Why do leaves turn colour in the fall?

Leaf color depends on the kinds of pigment a tree has inside its leaves.

In fall, cool temperatures and shorter days cause some pigments to break down and new ones to form.

Leaves look green all summer because of chlorophyll.

Chlorophyll helps the tree make food during the growing season.

In late summer, when nights get cooler, the chlorophyll in each leaf breaks down and disappears.

Soon the leaf is no longer green.

Why do leaves turn colour in the fall?

Yellow and orange pigments are in leaves all year, but you can’t see them in summer because they are covered up by all the green chlorophyll.

Once the chlorophyll breaks down in late summer, the yellow and orange show up. (These pigments are the same ones that make carrots orange and egg yolks yellow)

The bright red and purple colours of fall show up only in leaves of certain trees. Unlike the green, yellow, and orange pigments, these bright colours are made by trees only in the fall. That’s because they need cool temperatures at night and lots of sugar to form. Red maples for example, make a lot of sugar and have many of these red and purple pigments.

Why do leaves turn colour in the fall? There are certain trees,

such as oak trees, that don’t change to bright colors in the fall.

Their leaves look brown and drab.

These trees have a special chemical inside their leaves called tannin.

The tannin mixes with the yellow and orange and makes the leaves turn brown.

What type of weather will cause the brightest fall leaves?

A spectacular show of fall colours depends on the right amount of sunshine, rain, and cool temperatures.

Too much rain causes colours to fade.

Bright, sunny fall days with cool nights are the best.

Sometimes one half of a tree will be a different colour from the other half. That’s because one side gets more sunlight, which causes brighter colours.

Temperature is important too. Slowly cooling temperatures that don’t dip below freezing cause the brightest colours.

Tree Types

There are many thousands of different kinds of trees but all true trees are separated into two (2) basic classifications: Coniferous trees which are

also known as “evergreens” or “softwoods”

Broadleaved trees which are also known as “deciduous” or “hardwoods”.

NOTE: “hardwoods” are flowering plants and the “softwoods” are cone bearers.

Coniferous Trees Includes the pines, firs and other evergreens that

usually have narrow needles instead of broadleaves. The term “evergreen” comes from the fact that the

needles appear not to turn brown and fall to the ground at the approach of winter.

The evergreens do shed their needles however, they do it so slowly that there are always green needles on the trees. (One species of needle leaf tree is exceptional. The needles of the Larch Tree turn golden-orange and drop off in the fall.)

Coniferous Trees

Conifers (from the Latin word meaning “cone-bearing”) have their reproductive structures in male and female cones.

Seeds are loosely attached to the cone scales.

The male cones bear pollen which is usually carried by wind to fertilize the female cones.

Conifers grow all around the world, but particularly in the colder regions of North America, Scandinavia and Siberia.

Sounds are muffled by the evergreen boughs. The air is fragrant and still.

Deciduous Trees This group of trees includes the oak, maple,

aspen, poplar, birch and many others. These trees have broad, flat leaves instead of

needles. Broadleaved trees produce flowers and after

pollination these flowers develop seeds. The seeds are often enclosed in a hard nut or a

fleshy fruit. Although some deciduous trees are pollinated

by wind, many are pollinated by insects which are attracted by the color and aroma of the flowers.

Deciduous Trees

Broadleaved trees are most common in warm climates.

To survive in colder regions, they have evolved a form of “hibernation” in which they shed their leaves and become dormant (inactive) until spring.

The word “deciduous” means that the leaves fall off the tree when autumn comes.

Summary

Deciduous (loses its leaves in fall)

Coniferous (cone baring trees)

Shedding of Leaves

• shed leaves in fall • shed continuously (most do not shed leaves in one season)

Shape of leaves • broad-leafed or needle shaped

• needle-shaped leaves

Water retention

• leaves waxy topside and large surface area on underside, causing moisture loss

• thick, waxy coating reduces water loss from transpiration

Temperature resistance

• do not withstand temperature extremes

• do withstand temperature extremes