Rainforest

Teacher resource

Secondary

Education @ Adelaide Botanic Garden

Bookings

All visits, including self-guided, to the Botanic Gardens must be booked.

Self-Guided Excursions

Booking online:

https://www.environment.sa.gov.au/botanicgardens/education/schools-education/self-guided-

bookings

(a booking form can be found on this webpage)

Discussions and bookings with an education coordinator.

email: DEWNRBGSchools@sa.gov.au phone: 08 8222 9311

Guidelines when in the Garden

Students must be supervised at all times while in the Garden.

Before starting your walk please remind your group that:

Gardens are peaceful places for people to relax and enjoy.

Walking slowly and talking quietly ensures everybody and everything will enjoy the gardens.

Plants are fragile, touch them gently.

Flowers, leaves, bark, seeds etc. growing on plants or lying on the ground are there for all to

enjoy. When you have finished with plant material found on the ground always return it to

the garden.

Keeping to paths and not walking on beds or borders avoids damage to plants.

Risk Management

Water: The garden has a number of open water bodies and requires close supervision by

teachers and supervising adults.

Student ratio: DECD Adult to student ratio is recommended at 1:10, 1:6 for Early years and

Junior primary. Schools should refer to their own Risk Management Policies for excursions.

Weather: Excursions at the Adelaide Botanic Garden are outdoors so sun protection is

required, insect repellent at certain times of the year is recommended. Light showers are not

an issue in the gardens and at time enhances the experience. There are a number of sheltered

areas throughout the garden and raincoats are preferred to umbrellas.

Toilets: There are 5 groups of public toilets across the Garden as indicated on the maps.

Contents

Purpose and key idea of the trail

Australian Curriculum Connections

Before the excursion

Suggested pre and post visit activities

Trail Maps

Acknowledgements

Rainforests – an introduction

Teacher background information

Purpose and key ideas of the trail

Recommended year levels: years 8-10

Purpose:

This trail encourages students to consider a range of concepts associated with rainforests. It

requires students to use the information supplied and their own observations to learn about

rainforest ecology and the related social and environmental issues.

Key ideas:

Rainforest ecology and structure

Plant types and structures

Rainforest adaptations

Climate

Conservation issues

Indigenous people

Rainforest sustainability.

Students will investigate:

A range of plants in Botanic Park and The Bicentennial Conservatory in relation to climate,

biodiversity, adaptation, ecosystems and the environment.

Students are encouraged to observe, analyse, inquire, record, hypothesize and connect knowledge

they already have with new learnings.

TfEL: Provide an authentic context in which to engage learners and build their understanding whilst

using a range of learning modes.

Time:

Allow between 1 and 1.5 hours for this session.

Australian Curriculum Connections

General capabilities

Scientific literacy

Critical and creative thinking

Ethical Behaviour

Intercultural Understanding

Cross-curriculum priorities

Sustainability

Aboriginal and Torres Strait Islander histories and cultures

Year 8

HASS: Human causes and effects of landscape degradation (ACHGK051)

Year 9

HASS: Distribution and characteristics of biomes as regions with distinctive climates, soils,

vegetation and productivity (ACHGK060)

HASS: Human alteration of biomes to produce food, industrial materials and fibres, and the use of

systems thinking to analyse the environmental effects of these alterations (ACHGK061)

Science: Ecosystems consist of communities of interdependent organisms and abiotic components

of the environment; matter and energy flow through these systems (ACSSU176)

Year 10

HASS: Human-induced environmental changes that challenge sustainability (ACHGK070)

HASS: Environmental world views of people and their implications for environmental management

(ACHGK071)

Science: Global systems, including the carbon cycle, rely on interactions involving the biosphere,

lithosphere, hydrosphere and atmosphere (ACSSU189)

Before the excursion

Vocab introduction:

Key word Definition

Emergent The highest of the rainforest layers, it is where the very tallest trees break through the

canopy. This layer is over 45m from the ground and is wet, hot and windy.

Canopy The branches and leaves of most of the rainforest trees. It is usually 30 and 45 metres

from the ground. More plant and animal species live in this layer than anywhere else in

the rainforest.

Understory Small trees and shrubs able to live in low-light conditions form the understory.

Forest floor The dark and damp ground layer where the rainforests largest animals are located.

Parasite An organism which lives in or on another organism (its host) and benefits by deriving

nutrients at the other's expense.

Epiphyte The word epiphyte (epi=upon, phyte = plant) means plants that grow on other plants, and

they can be seen throughout rainforests.

Growing on other plants for support is their way of getting a share of the light and rain

that falls through the canopy. They are not parasites, but instead obtain nutrients by

collecting falling leaves and moisture.

Climate change A change in global or regional climate patterns, in particular a change apparent from the

mid to late 20th century onwards and attributed largely to the increased levels of

atmospheric carbon dioxide produced by the use of fossil fuels.

Carbon emissions Carbon dioxide (CO2) is a colourless, odourless and non-poisonous gas formed by

combustion of carbon and in the respiration of living organisms and is considered a

greenhouse gas. Emissions means the release of greenhouse gases and/or their

precursors into the atmosphere over a specified area and period of time.

Tropical rainforest Rainforests characterised by a warm and wet climate with no substantial dry season.

Tropical rainforests are typically found within 10 degrees north and south of the equator.

Temperate rainforest Rainforests found in temperate regions, usually having a more even canopy than tropical

rainforests but lacking the palms and climbers and level of plants diversity of a tropical

rainforest.

Photosynthesis The process by which green plants and some other organisms use sunlight to synthesize

nutrients from carbon dioxide and water. Photosynthesis in plants generally involves the

green pigment chlorophyll and generates oxygen as a by-product.

Convergent evolution The process whereby organisms not closely related (not monophyletic), independently

evolve similar traits as a result of having to adapt to similar environments.

Buttress roots “Buttressing” is a common feature of the larger and often emergent rainforest trees.

Buttresses are flanges at the lower part of the trunk. They not only provide anchorage for

large trees in shallow rainforest soils, they also help obtain oxygen from the air to

compensate for a lack of it in the wet soil and composting leaf litter.

Suggested pre and post visit activities and discussions

As a Subject Teacher in High School, considering this Rainforest trail when designing learning for

students may generate a raft of relevant opportunities. This includes discussion around climate

change and its impact globally and locally.

Examples include:

Map locations of rainforests throughout the World – what can you find out about them?

Research plant, insect and animal species native to a particular rainforest around the world or

in Australia.

Research Indigenous groups from around the world that depend on rainforests for their

everyday lives.

Develop strategies we can adopt to help save our rainforests. Find out what is being done

today to help this cause – a good start is to watch this TED talk -

https://www.ted.com/talks/topher_white_what_can_save_the_rainforest_your_used_cell_phone

#t-15951

Research as many foods as you can that have their origins from rainforest.

Research how many medicines you can that have their origins from rainforests (eg, quinine to

help malaria).

Find out as much information as you can about the Titan Arum (Amorphophallus titanum). A

good starting point is this webpage -

https://www.environment.sa.gov.au/botanicgardens/blogs/around-the-gardens/170118-

corpse-flower-time-lapse

At certain times of year this unique rainforest plant can be found in the Bicentennial

Conservatory. Come back and visit it when it is flowering!

Layers of a Rainforest

Emergents

Understorey

Canopy

Forest floor

Map

Rainforests – An Introduction

What do we know about rainforests?

A rainforest is essentially as its names suggests….a forest that grows in areas of high rainfall. A

forest is defined as an area covered by trees that grow so close together that the canopy is

interlocked in such a way that direct sunlight does not reach the ground at all, except in small

patches.

A rainforest generally needs at least 1500mm a year of rainfall, falling consistently.

Tropical rainforest cover a large part of the planet and are characterised by a warm and wet climate

without a large dry season.

Although tropical rainforests cover a large part of the planet, we also have temperate rainforests

occurring in a few regions around the globe, including Australia. Temperate rainforests are found in

cooler climates with less rainfall per annum.

Whilst the spotlight is quite often on rainforest regions overseas such as the Amazon, Australia has

some of the largest and oldest areas of rainforest on the planet, with some dating to the super

continent of Gondwana (this region of Gondwana Rainforest spreads over 50 separate parks in

northern NSW and South East Queensland).

So, why are rainforests so important?

To answer this question, let’s look at some facts about rainforests……

Rainforests cover only about 2% of the Earth’s total surface. However between 40 and 75%

of all plants and animals on the earth live in rainforests!

Rainforests cover approximately 3% of Australia, but contain more than half of all Australian

plant families and 30% of the countries bird and mammal species. This includes frogs,

snakes, bird and marsupial species.

300 species of plants can be found in a rainforest region in Western Australia that cannot be

found anywhere else in the World!

Tropical rainforest are often called the “World’s lungs” due to the facts that they account for

28% of the oxygen turnover (the biggest oxygenator is sea algae!). This is due to their ability

to store massive amounts of carbon in their tissues via the process of photosynthesis and

breathe out oxygen.

Tropical rainforests are also known as the “world’s largest pharmacy” due to the fact that

around 25% of nature’s medicine have been discovered there. This includes over 2000 plants

that can be used to help aide in cancer treatment because of their anti-cancer properties!

Many new medicines are also believed to be undiscovered – less than 1% of the species of

plants in rainforests have been analysed to determine their value for medicine.

Many of the foods we eat today have their origins in tropical rainforests. These include

bananas, coffee, avocados, mangoes, cacao and papaya to name a few!

The largest rainforest in the world is the Amazon in South America. It is so large that if it

were to be a country, it would be the ninth largest in the world!

The canopy is so thick in some rainforests around the world that it can take a drop of water

ten minutes to travel from the canopy to the forest floor!

The situation today….

It is estimated that each and every day we lose around 80,000 soccer pitches worth of rainforests

around the world (or over 30 million soccer pitches each year)! That also equates to around 5 billion

trees every year.

The main reasons for the loss of rainforests worldwide (deforestation) is industrial agriculture

production of commodities like Palm Oil fabric, paper and logging.

This can have a significant effect globally.

If this continues we can expect to lose 5-10% of rainforest species in the next decade.

Even today, rainforests provide a home for many indigenous people around the world. The forest is

their source of food, fresh water, shelter, medicine, culture and religion.

Many rainforest food plants have been adapted and bred for mass production on farms and large

scale plantations. This leaves them susceptible to diseases and pests (think the great potato famine

in Ireland). To maintain food production we need forests which provide wild species with resistance

to these problems.

As mentioned above, rainforests have been referred to as the “world’s largest pharmacy” as many of

the medicines we use today come from rainforest plants. With only 1% of these species so far being

analysed for medicine, many potential new medicines can be derived from rainforest plants.

Deforestation threatens this potential.

Tropical rainforests play an important role in being able to store significant amounts of carbon

emissions, stored in tree trunks, as the forests grows. Cutting downs these forests for wood, pulp,

paper and for other uses as well as forest fires, releases large amounts of carbon in to the air.

Burning in the Amazon forest alone is believed to contribute to 20% of the World’s CO2 emissions

and in turn global warming.

Teacher background information

This section provides teachers with background information on each plant or station. Extra

enrichment information is provided in text boxes, which can be used to prompt student inquiry

throughout the trail.

Finding the plants:

The plants on this trail may be found by referring to the map and by looking for the plant

nameplate. The plants may be visited in any order. There is also a photo match of the plant to

ensure you are in the right place.

Allow between 1 and 1.5 hours to complete the trail.

STATIONS

Begin outside the Conservatory in Botanic Park (See the garden map)

1. Ficus thonningii - Strangler Fig

Key Ideas: There is great diversity of life in rainforests. Plants and animals are

interdependent. Plants need sunlight to grow.

Although not growing as a strangler here this plant is capable

of such growth in its natural habitat.

Stranglers often start from seed dropped by fruit eating birds,

possums or bats high in the upper canopy where the young

seedling is able to gain an early growth advantage due to the

increase in available light.

The twisted pattern of the trunk and aerial roots gives an idea

of its ability to encircle a host tree.

The strangler fig may weaken the host by shading it from

sunlight and vigorously competing with it for nutrients from the

soil. It can eventually kill older host trees that cannot cope with

the rapid and aggressive growth of the strangler.

Aerial roots indicate the plant comes from a region of high

humidity.

2. Mosses and Lichens, - Epiphytes

Key Ideas: Some rainforest plants live off the ground to get more sunlight.

In a fork on the eastern side of this tree is a young fig that provides a

good demonstration of how a strangler fig begins its life.

Also notice the mat-like covering of mosses and lichens growing on the

tree trunk.

Plants like these that grow on other plants without harming them are

called epiphytes. They are very common in rainforests.

Although they live away from the soil, and have the problem of less water

and mineral nutrients, epiphytes have the advantage of more available

light higher up in the canopy and less competition from the plants

growing down below.

Further examples of epiphytes will be seen in the conservatory.

3 Canopy Layer - Upper Canopy

Key Ideas: The canopy layer changes the physical conditions for life in the understory.

Before moving into the circle of canopy trees

near station 4, find a sunny open space and ask

the students to note the factors of the climate

such as temperature, sunlight, wind and

humidity. Now move to the circle of trees and

ask students to note the reduction in the

temperature, light and wind. An increase in

humidity would be harder to notice.

Looking up towards the tops of the trees

students should note the canopy layer. The

canopy layer reduces sunlight by up to 95%.

The lack of light reaching the ground means

many plants are epiphytes or climbers in the

rainforest or they have adaptations to low light intensities. Note the lack of sun loving lawn growing

under the canopy.

4. Ficus macrophylla – Moreton Bay Fig

Key Ideas: Rainforest soils are generally shallow. Logging of rainforest can lead to long term,

irreparable damage.

The large, shallow buttress roots help support the tree, absorb nutrients (generally found only near

the surface of rainforest soils) and take in oxygen.

Broad scale, indiscriminate logging of large trees and

the subsequent loss of soil binding roots and

protective canopy leads to large scale erosion of

rainforest soil.

Hundreds of epiphytic plants living on such trees may

also be lost when just one large canopy tree is

removed.

5. Agathis robusta - Kauri Pine

Key Ideas: Rainforest grows in layers. Plants have designs that help them grow in different

layers.

Stand near the Conservatory Gate and look to the right of

the conservatory for these two large trees.

The Kauri Pine is in the foreground, the Bunya Pine is

behind and to the right. As in a rainforest they appear to

emerge from the canopy below. Now walk to the base of

the Kauri.

The tall straight trunk of the Kauri Pine has branches and

leaves only towards the top. This design is ideally suited

to maximising light capture. The domed crown of the

Bunya Pine in the background is also well designed for

this purpose. Unfortunately, emergents make ideal

logging specimens.

Inside the Conservatory: (See the Conservatory map)

6 Molineria capitulata - Weevil Lily

Key Ideas: There are many diverse plants in the rainforest with unusual features.

Molineria is unusual in that the flowers are not

displayed above or within the leaves like most

flowering plants.

Its yellow flowers can be found attached to the

main stem just above the ground.

Ground dwelling ants, beetles or small

marsupials may pollinate the flowers rather than

birds or flying insects.

A weevil is one particular known pollinator.

7 Angiopteris evecta, - King Fern

Key Ideas: Australia has some of the most ancient rainforest plants on the earth.

Angiopteris is an ancient fern with ancestors

going all the way back to when Australia was

once joined to Antarctica as a part of the super

continent Gondwana. Today, it is the only

representative of the ancient genus Angiopteris

that has been growing in Australia for about 200

million years. More modern Australian rainforest

plants have migrated from Asia.

It is reputed to have the largest frond of any fern

on earth, growing up to 8 metres in length. They

have no strengthening tissue and the frond relies

upon internal water pressure to stay erect.

Spores, held in cases called sori, line the edges of the undersides of the frond.

Angiopteris prefers to grow in streams and gullies. It is a spectacular plant that has great

horticultural value as an indoor and outdoor plant.

8 Syzygium moorei, - Rose Apple

Key Ideas: Large areas of rainforest have been cleared for agriculture. Actions can be taken to

conserve threatened rainforest habitat.

This plant has lost most of its original habitat due to

clearing for growing sugar cane. Like many other rainforest

plants cleared for agriculture, the continued survival of this

species is under threat. Remnants of the original population

of these trees are found only along the edges of

Queensland coastal ranges growing along the limits of its

original range.

Stands left remaining on private property are threatened by

future clearing.

Greater numbers need to be included in reserves before it

can safely be preserved in the wild state. Acquisition of

private land may assist the species preservation.

Botanic Gardens can help by:

collecting seed to propagate wild plants

education

scientific research to ensure the species survival.

9 Linospadix monostachya - Walking Stick Palm

Key Ideas: Rainforest plants have many different uses.

The narrow straight trunk, attractive bamboo-like rings and

strength meant thousands of these small palms were

harvested during World War 1 to make walking sticks for

returned wounded soldiers. A comfortable handgrip was

carved from the compact root ball found underground at the

base of the stem.

The small cabbage formed at the growing tip is edible as are

the ripe small red fruits.

10 Barringtonia calyptrata, - Fish Killer Tree

Key Ideas: Rainforests are home to millions of people around the world. The forest provides for all

their needs.

You can locate this tree behind the seat.

People that live in rainforests have many different uses for

plants.

Poisons from the bark and fruit of this tree can be used to

stun and catch fish.

Aboriginal people would also use the leave as a medicine to

help fever and chest pain.

Look for the unusual flowers and fruits hanging from long

string-like stems. The fruit are particular enjoyed by

Cassowaries, giving it another name – the Cassowary Pine.

11 Asplenium nidus - Birds Nest Fern

Key Ideas: Because epiphytes live off the ground, they have special designs to capture water and

nutrients.

Epiphytes such as this are prolific in the rainforest, growing on the

trunks of larger trees without harming them.

The spongy base, which resembles a bird’s nest, has fibrous material

capable of trapping and holding water.

The funnel-like display of leaves channels water and debris falling

from above to the centre of the plant.

When decomposed the debris or food leftovers brought into the

centre of the plant can also be a source of mineral nutrition.

12. Nauclea orientalis - Leichhardt Tree

Key Ideas: Indigenous people can lose their whole way of life when rainforest is destroyed.

This tree has numerous traditional Aboriginal uses.

Aboriginal uses of this tree include: canoes, fish poisons,

medicines, yellow dye and pain-killers. The bitter fruit can also

be eaten.

Most tropical rainforests have been cleared for agriculture.

Rainforest is being lost at over 1 hectare per minute.

Over 100 million indigenous people still depend directly on

rainforest, using it as their primary source of food, shelter,

culture, medicine and religion.

Without the rainforest these people suffer total loss.

Many of these former forest dwellers find only poverty and a

reduced quality of life when forced to move to nearby cities.

13 Leaf Litter

Key Ideas: The litter layer is vital to the health of rainforest.

Many different stages of decaying leaves can be seen on the

ground at this spot.

Large amounts of dead leaves, flowers, fruits and branches are

shed from the rainforest canopy each year. This can be up to 8-

10 tonnes/hectare annually. This litter is decomposed quickly by

small insects and fungi that quickly return nutrients to the soil

for the plants to re-use.

The process is rapid due to the warm, moist conditions on the

forest floor. Insects and fungi can be seen amongst the litter at

this stop.

This thin, recycled surface layer of nutrients is vital to the rapid

growth of rainforest plants yet it is quickly leached away and lost

when the forest is cleared.

14 Pandanus oblatus

Key Ideas: Some rainforest plants have adapted to very wet, flood prone soils.

The upright, aerial roots hold up the central trunk and give

the impression the plant is perched on stilts.

The stilt roots reduce the force of water during floods and

raise the plant above advancing water levels.

Organic material trapped between the roots decays over

time and releases nutrients.

The aerial roots also more easily obtain oxygen than roots

in waterlogged soils.

15 Alocasia macrorrhiza - Elephant Ears – Drip Tip leaves

Key Ideas: Constant moisture causes problems for plants. Plants have designs for dealing with this

problem.

The smooth waxy coating, near vertical angle and sharply pointed

drip tips all contribute to rapidly getting rid of water from the

leaves.

These structures are best seen on new complete leaves.

A good example of a rainforest leaf covered by other plants can be

seen in the photographs on the western wall at the city end of the

conservatory.

16 Alpinia caerulea, - Native Ginger

Key Ideas: Aboriginal people have many different traditional uses of rainforest plants.

Aboriginal people chewed the seeds inside the ripe, bright-blue,

fleshy outer covering of the fruits of this plant.

The ginger tasting tips that emerge from the roots are also edible.

The leaves were wrapped around food prior to cooking.

When woven they made a covering for shelters.

17 Climbers

Key Ideas: Some plants are climbers to increase their share of sunlight at the top of rainforest.

Climbers are a common part of the rainforest, expending less energy to reach the light at the upper

canopy than trunk building trees.

Have a good look around this area – climbers are using a variety of

methods to reach the light above.

At the top of the stairs you will find the Pothos (pictured) which uses

its claw shaped roots to climb the trunk of the Palm tree and pull itself

up into the canopy. Opposite this is another climber on the trunk

(Faradaya splindida) uses a spiralling stem to achieve the same

purpose.

A relative of the black pepper plant (Piper) is also found throughout the

conservatory and climbs its way up high in search of light.

Climbers may eventually compete with the trees that support them for

light, water and mineral nutrients.

Large woody climbers are called lianas and may run for a kilometre in length through the rainforest.

18 Licuala spinosa – Mangrove Fan Palm – Large Leaves

Key Ideas: Leaf design maximises sunlight capture under the canopy.

The native home of this palm is the moist areas

of southeast Asia.

Due to low light intensities on the rainforest floor

understorey plants often have large leaves to

maximise the amount of sunlight they can

absorb.

Pleats in the leaves increase the surface area for

light absorption. They also add strength to the

leaf and prevent it from flopping down.

The stems are also green to increase the area for

photosynthesis.