Environmental Education to Form-3 students in Mwanga, Tanzania
Liana, 2014 (www.liana-ry.org)
Functions of trees in ecosystems
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Objectives
1.
Students can describe the concepts of ecosystems and ecosystem services, trees
2.
Students can describe ecosystem services provided by trees and that trees are
like habitats within habitats providing shelter, food, nesting place, hunting ground for many
other organisms including human beings
3.
Students are able to describe the function of a fig tree in East Africa (film)
Materials needed for the lesson
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Flip chart papers: collect answers to a blank paper twice.
Ecosystem services: four categories
Flip chart 1. Ecosystem services of trees
Flip chart 2. Trees as habitats
Film: Shortened version of ‘The Queen of Trees’ https://www.youtube.com/watch?v=KMNPZPYCCw4
Leave-to-do task:
1. Identify all the trees in the school compound and label them with the local name and the
botanical name
2. Study in detail Tanzania’s ecosystems, biodiversity and the threats Tanzania’s nature and
ecosystems are facing.
 Make 2 posters of all the Ecosystems (one poster is a map, the other describes the
ecosystems… Chapter 1)
 1 poster about the Species diversity (Chapter 2 Diversity and conservation)
 1 poster about Agricultural diversity (Chapter 2 Diversity and conservation)
 1 poster about Protected areas and conservation priorities (Chapter 2 Diversity and
conservation)
 1 poster about Ecosystem products (Chapter 3)
 1 poster about Ecosystem services (Chapter 3)
 1 poster about Non-Material benefits (Chapter 3)
 1 poster about Habitat loss and degradation (Chapter 4)
 1 poster about Overexploitation of high-value species (Chapter 4)
 1 poster of Invasive species (Chapter 4)
 1 poster about Pollution (Chapter 4)
 1 poster about Climate change (Chapter 4)
Materials to be left for the clubs:
 13 large manilla papers
 Marker pens of black, red, green
 Printed reading material: State of environment report of Tanzania
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Environmental Education to Form-3 students in Mwanga, Tanzania
Liana, 2014 (www.liana-ry.org)
Sequence of the lesson
List to the students the learning objectives as above
1. Ensure concepts are understood: Elicit from the students and help to get the
definitions
Tree: In botany, a tree is a perennial plant with an elongated stem, or trunk, supporting branches and
leaves in most species.
Habitat: A habitat is an ecological or environmental area that is inhabited by a particular species of
animal, plant, or other type of organism.
Ecosystem: An ecosystem is a community of living organisms (plants, animals and microbes) in
conjunction with the nonliving components of their environment (things like air, water and mineral soil),
interacting as a system.
Flip chart 1:
Ecosystem services: Services that ecosystem provide. They are divided into four broad categories:
1. supporting, such as nutrient cycles and crop pollination
2. provisioning, such as the production of food and water
3. regulating, such as the control of climate and disease
4. cultural, such as spiritual and recreational benefits
2. The ecosystem services that trees provide (Flip chart 2)
1. Water storage and retention – Forests catch, hold and recycle rainwater, moderating water flows.
Plants absorb rainwater and then release it back into the air.
2. Erosion control – Retention of soil within an ecosystem.
3. Carbon and oxygen cycles – Plants absorb carbon dioxide and release oxygen back into the air,
creating a breathable atmosphere.
4. Nitrogen Cycle – Nitrogen is essential for plant growth. Bacteria living on some tree roots convert
nitrogen from the atmosphere into a form that the tree can use. Creatures feeding on these trees
release nitrogen in their waste products. When the waste is broken down it is released back into
the atmosphere.
5. Harbouring pollinators – This can be vital to the success of some of our food crops.
6. Biological control – Many predators of crop pests survive on alternative prey in hedgerows ready
to disperse once pests appear.
7. Refugia – Trees act as nurseries and habitats. Trees are refugia for woodland species in the
farmed landscape.
8. Food production – Nuts, fruits and berries.
9. Energy and building materials – firewood and timber
10. Transforming energy from the sun into stored chemical energy – This is the foundation for
virtually all food webs.
11. Genetic resource – Some tree species exist as sub-populations of locally adapted species.
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Environmental Education to Form-3 students in Mwanga, Tanzania
Liana, 2014 (www.liana-ry.org)
12. Carbon sequestration – binding carbon from the atmosphere. Mitigation of anthropogenic climate
change.
13. Provision of sites for particulate deposition –Trees can reduce the effects of pollution by
intercepting them on their leaves and thus having a filtering effect on the air.
14. Cultural and esthetic value
Provide a short introduction to the film.
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It is a film about a sycamore fig tree in East Africa.
The story is about the services the tree provides to other organisms
It is also a story about the extraordinary pollination of the tree
o the tree does not have visible flowers
o flowers are inside the figs/fruits into which the fig wasp bores itself, hatches and is then
released in order to fly away and take the pollen of the tree with it to another tree
When you watch it try to keep in your mind all the creatures that benefit from the tree (don’t
write while watching, concentrate in watching only)
Show the film (17 min)
3. Tree are habitats within habitats
 Ask students which creatures the fig tree provides and what it provides to them (e.g. nesting site
to a hornbill, sugar for beetles, ants eat the sugary feces of the beetles…)
 List the answers on a flip chart as they come, add more if they don’t remember
Introduce the leave-to-do task.
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