CURRICULUM FOR EXCELLENCE Science – Second/Third/Fourth Levels – page 1
The Ancient
Tree Hunt
SCIENCE:
ROOTS FOR SURVIVAL
UNIT 5 :TEACHERS NOTES
• Investigating roots – from seed to tree
• Investigating root architecture
• Investigating root tips
Learning outcomes
By undertaking these activities learners will be able to:
• Investigate the environment through careful observation,
comparison and recording
• Handle and present data in ways helping analysis and
interpretation.
• Organise, plan, carry out and evaluate a practical
experiment – establishing a tree nursery in the school
grounds
• Describe skills from other disciplines helping in
communicating and presenting scientific understanding.
• Demonstrate a secure understanding of key ecological
concepts of science – adaptation, change, cycling, energy
flow, interdependence, and how plants/trees grow.
• Describe the function and behaviour of roots and root
cells, and explain how these may provide a means of
survival for (ancient) trees.
• Explain how firsthand experience aids their knowledge
and understanding.
CURRICULUM LINKS:
Through their activities learners should discover how
science can be interesting in explaining the world around
them, and how it offers opportunities to ask questions and
find explanations. They will make progress as successful
learners, gaining confidence through their achievements,
and understanding the important role roots play in the
survival of all trees, but especially ancient trees.
This unit directly meets targets within the 5-14
Curriculum Guidelines for Environmental Studies –
Society, Science and TechnologyTechnology levels
D/E/F – Science: knowledge and understanding - the
processes of life and interaction of living things; skills
exemplification and developing informed attitudes. It also
meets wider subject and cross-curricula outcomes in
English Language, Mathematics, Expressive Arts,
ICT and Citizenship.
Within the developing Curriculum for Excellence 3-18
it provides a context for learning supporting all four
capacities– successful learners, confident individuals,
responsible citizens and effective contributors. Within the
experiences and outcomes, it meets some of the current
(April 2008) Science outcomes under Planet
Earth/Biodiversity and Life and Cells/Cells at second, third
and fourth levels:
Biodiversity: SCN205B, SCN406B Bio, SCN 408B Bio
Cells: SCN316N, SCN427 N Bio
The unit may also be developed alongside other curriculum
areas – Social Studies, Expressive Arts, Languages and
Technologies – and cross-curricular areas, such as ICT,
Determined to Succeed, Health Promoting Schools, and
citizenship/Eco Schools through the outdoor learning
component.
3720/06/08
Take a look at the other curriculum areas in this Ancient
Tree Hunt teaching and learning resource series.
These sheets have been designed to be shared. Feel free to photocopy and provide to colleagues.
The Woodland Trust is the UK’s leading woodland conservation charity dedicated to the protection
of our native woodland heritage. www.woodlandtrust.org.uk www.AncientTreeHunt.org.uk
CURRICULUM FOR EXCELLENCE Science – Second/Third/Fourth Levels – page 2
The Ancient
Tree Hunt
SCIENCE:
ROOTS FOR SURVIVAL
UNIT 5: TEACHERS SHEET
Activity 1:
Investigating roots – from seed
to tree
Identify an area of the School Grounds for a tree nursery
What to do
Advice/help – as required
It is possible in most school grounds to create a small,
manageable tree nursery, using old fish boxes, or raised beds –
made from wood or old car/tractor tyres.
There are plenty of sources of advice – the local Ranger Service,
Forestry Commission, Natural England or RSPB office. Also
look at the Woodland Trust website, and go to Seeds to Trees
educational pages, for KS2 Science, which describe how to
grow and look after oak acorns and birch seeds.
Explain that this investigation, being followed up over a longer
period than a few lessons, will help them find out how tree
roots and trees grow. They will be collecting and planting tree
seeds and recording their growth over time. Once they are
large enough to plant out, they may decide whether this should
be in the school grounds, or somewhere in the wider
community. Their trees will not become ancient in their
lifetime, but they may in a few hundred years time, for future
generations of their family.
Involve the whole class in planning the operation, and
organising specialists to come into school to advise them, or
research aspects for themselves. By facilitating their questions
help them to organise permission for the tree nursery, select
the best site, decide what materials they need to create and
protect it, find out what treatment the seeds need (do they
need freezing, or just left out) before they plant them, how
they plant acorns, hazelnuts, compared to birch seed or
hawthorn/rowan berries etc.
Organise a local site to collect seed, bring it back to school,
treat (as required) and plant the seeds out in seed trays, or
pots (recycle yoghurt/margarine tubs) depending on what is
being planted. Plant many more than you need. Find out why
native trees, of local provenance, are favoured by most
environmental conservationists.
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Equipment needed:
Fish boxes (or other old plastic crates), raised beds, tyres
Local tree seed source/s
During the weeks and months following, watch the seedlings
grow and look after their watering. If you wish to extend the
experimental aspect, grow the seedlings in different kinds of
soil/compost and different drainage conditions.
As they grow, carefully uproot a seedling, and examine the root
systems as they develop. Make and record measurements of
height and length regularly – draw graphs and interpret.
Connect their findings with their learning about trees generally,
and ancient trees in particular. Explore whether
seedlings/saplings grow better if uprooted for observation or
not – why might this be? [uprooting seedlings/saplings damages
the root tips and root hairs]
Transfer the seedlings into the tree nursery as they grow large
enough to survive out of doors. Build in to the planning the
care of the trees in the tree nursery in the long term – by
helping the students organise a rota, or handing over to future
Science students, or the Eco-committee/Pupil Council. Also
identify sites for planting out the trees after 2-3 years – school
grounds, local wildlife reserve, local old folks home etc..
[Depending on the structure of your curriculum in school, it
might be possible to time the planting of tree seeds, some
months before covering this part of the course. Or, better, if
the school has a tree nursery it will be possible to investigate/
demonstrate the points to be made, at most times of year.
Otherwise, plan to plant some acorns or birch seed in advance
for this demonstration in the next school year, perhaps with
another class.]
These sheets have been designed to be shared. Feel free to photocopy and provide to colleagues.
The Woodland Trust is the UK’s leading woodland conservation charity dedicated to the protection
of our native woodland heritage. www.woodlandtrust.org.uk www.AncientTreeHunt.org.uk
CURRICULUM FOR EXCELLENCE Science – Second/Third/Fourth Levels – page 3
The Ancient
Tree Hunt
SCIENCE:
ROOTS FOR SURVIVAL
UNIT 5: TEACHERS SHEET
Activity 2:
Investigating root architecture
Equipment needed:
Copies of Student Information Sheet 5/S1, Student
Activity Sheet 5/S2 and Student Activity Sheet
5/S3 – one each
What to do
Ask the class to stand up, imagine a high wind is blowing – will
they feel steadier in the wind when they stand with their feet
together, or slightly apart? The answer should be the latter. So
it is with trees. If you look at the trunk of most trees, even
ancient ones, they are wider at the bottom than at the top.
How do scientists investigate root systems that are
underground?
What is the science behind this? Weight for weight, one thick
rod is better at resisting bending than several thin ones. So,
trees use a single trunk and can support a crown of leaves
using the minimum of wood, and, therefore, energy. The
tapering also minimises the wood they use, the bending forces
are greatest at the base of the trunk – that’s where it is
thickest. What other adaptations do trees have in resisting
environmental stresses e.g. high winds? Can they come up
with suggestions? Here are a couple:
Show a picture of a fallen tree and root plate. How else might
you investigate tree roots? [scientists use trenching, detailed
excavations and soil coring.]
• Reshaping their profile above ground
• Developing a root system below ground
Experiments in wind tunnels have shown that the way thin
branches and twigs, of a tree’s crown can blow around allows
the tree to ‘reconfigure’ itself, to be more streamlined. This
reduces the aerodynamic ‘drag’ force it transmits to the trunk.
For conifers (5 m high) it can reduce the force by a third. For
broadleaves, the value is even better. Even the leaves, e.g. ash
and sycamore, can roll up to be streamlined tubes, and more
rigid leaves, e.g. oak and holly, flatten themselves against the
branches, to reduce resistance. Have a look next time it’s a
windy day.
The storm/hurricane of October 1987 in the SE of England
provided for a lot of new information to be gathered, from the
root plates of windblown trees.
An ancient oak tree in England was found to have lateral roots
still 2.5cm in diameter, over 50m from its trunk, using careful
coring and excavation.
Using the tree seedlings/saplings (from Activity 1), visit or use a
photo image of, a windblown tree with its ‘root plate’,
combined with the Student Information Sheet 5/S1
Investigating Root Systems and Student Activity Sheet 5/ S2
– Investigating Root Architecture explore what the information,
images and diagrams tell them about the differences in tree
root systems, and how they change over the life of a tree.
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This unit will explore the second suggestion – developing a
root system below ground. Root systems are well designed,
mechanically, to anchor them firmly in the soil, but they are
difficult to study without destroying the tree in the process.
These sheets have been designed to be shared. Feel free to photocopy and provide to colleagues.
The Woodland Trust is the UK’s leading woodland conservation charity dedicated to the protection
of our native woodland heritage. www.woodlandtrust.org.uk www.AncientTreeHunt.org.uk
CURRICULUM FOR EXCELLENCE Science – Second/Third/Fourth Levels – page 4
The Ancient
Tree Hunt
SCIENCE:
ROOTS FOR SURVIVAL
You may design a worksheet, or ask them to develop a mind
map, that draws out the main points.
Including:
• Root systems change and adapt over time, with the tree –
they transport water and nutrients, and act as food storage
during dormancy (winter).
• The tap root is crucial in the early stage of growth to all
trees, acting as a stake
• Tap roots are less important as the tree matures, and will
die/rot; replaced by secondary roots.
• Lateral roots provide anchorage, like guy ropes on a tent,
preventing rotation.
• Lateral roots become more important, become thicker and
branch.
What can happen when an ancient tree is blown over, or dies –
is that the end? Make the connection back to ‘phoenixing’ –
see Unit 2 Ancient Trees and Survival Strategies –
Activity 3 New Life from Old Growth, and to the information at
the end of the Student Information Sheet 5/S1. Encourage
everyone to reflect on what this new science means for the
way we care for ancient trees.
The biodiversity value of these root systems is another reason
for protecting our amazing heritage of ancient trees. Scientists
are only just beginning to unravel the fascinating complexities
of what lies in these roots below ground level. The more we
know, the more we realise what we might not know. This is
the thinking that lies behind applying the ‘precautionary
principle’ in the sustainable management of our environment,
and its biodiversity, including ‘the jewels’ like ancient trees.
• A network of superficial roots develops through the top
soil to the edge of the crown, and in many cases beyond.
• When lateral roots are no longer able to provide firm
anchorage – ‘sinker roots’ descend vertically down to add
stability and absorb water/nutrients from lower down.
Ask them to think back to what they learnt about how trees
adapt over time, to become ancient trees? What effect do
they think this may have on the root systems of the trees?
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Give out Student Activity Sheet 5/S3 Roots for Survival and
ask the students to annotate the diagram, or create their own,
extracting the information they need from the Student
Information Sheet 5/S1.
These sheets have been designed to be shared. Feel free to photocopy and provide to colleagues.
The Woodland Trust is the UK’s leading woodland conservation charity dedicated to the protection
of our native woodland heritage. www.woodlandtrust.org.uk www.AncientTreeHunt.org.uk
CURRICULUM FOR EXCELLENCE Science – Second/Third/Fourth Levels – page 5
The Ancient
Tree Hunt
SCIENCE:
ROOTS FOR SURVIVAL
INFORMATION SHEET 5/S1: STUDENT SHEET
Investigating Root Systems
All trees have a structural adaptation for resisting being blown
over by the wind – roots. The tree’s root system is essential,
because despite their ability to streamline, trees still transmit
large wind forces downwards. Trees depend on the root
system’s ability to resist and keep the tree standing.
Sometimes you see windblown trees with a wide ‘root plate’ –
this is the result of a force greater than the root system’s
ability to resist – the roots snap.
• Growing aerial roots – aerial roots can be seen high up
the trunk of veteran/ ancient trees. They may stretch over
4m from high up in a hollow tree down into its base. Here,
inside the base of a hollow tree, minerals and nutrients
released from the heartwood decay have built up. The
aerial roots tap straight into this food supply – the
minerals/nutrients are transported and recycled once again
– creating new living plant tissues.
The development of a tree’s root system is influenced by
several factors to do with
• Growing buttress roots – Ancient trees growing in the
open often develop these large roots growing out from the
trunk, partly above ground, spreading in all directions to
anchor the tree in high winds.
a) the tree – species, age and health, planting density,
management (pollarding/ coppicing), and
b) the environment – slope angle, soil type and depth,
stresses (e.g. wind, drought etc).
We are now finding that root systems can vary even within a
single species, and/or over time
Generally, although tree roots can extend to depths over 3m,
most do not extend more than 2m, and 80–90% are in the top
60cms of soil. Much depends on the properties of the soil –
low moisture and low mineral/ nutrient levels may encourage
deep rooting, while shallow or compacted soils, and poor
aeration may inhibit root growth.
As the tree ages beyond maturity, some have called the tree’s
process of reducing its crown and hollowing out – ‘growing
down’. We have found that the root systems of the trees are
also affected. There are 3 main growth responses helping a
tree’s continued survival:
The root system has several parts to play in the life, survival
and role of one of our largest living organisms – trees. It
supplies essential water and minerals for the tree to grow. It
also supports its own community of other species, e.g.
mycorrhizal fungi, contributing to its biodiversity.
The more scientists research the more they are finding that
roots play an important biodiversity role, even in death.There
are distinct communities of bacteria, fungi, and invertebrates
associated with root decay ecosystems, and recycling their
woody matter. These communities are very specialised, and
associated species are often very rare, especially when
associated with ancient trees.
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• Root system reduces in size – the lower height and
reduced spread of branches of the tree means the root
system is far more efficient – far less energy is needed in
moving the water and minerals from the roots to the
branch extremities, and returning the plant sugars to feed
the root mycorrhiza, and fewer roots are needed.
These sheets have been designed to be shared. Feel free to photocopy and provide to colleagues.
The Woodland Trust is the UK’s leading woodland conservation charity dedicated to the protection
of our native woodland heritage. www.woodlandtrust.org.uk www.AncientTreeHunt.org.uk
CURRICULUM FOR EXCELLENCE Science – Second/Third/Fourth Levels – page 6
The Ancient
Tree Hunt
SCIENCE:
ROOTS FOR SURVIVAL
ACTIVITY SHEET 5/S2: STUDENT SHEET
Investigating root architecture (Label the trees below)
Scientists have identified 3 broad groups of root system in the past.
•
Surface root systems – large horizontal, lateral roots extend just below soil surface, from which
‘sinker roots’ branch – growing vertically down from lateral roots, quite close to the trunk – ash, aspen,
Norway spruce
•
Heart root systems – both larger and smaller roots descend diagonally from the trunk – Silver and
Downy birch, European beech, lime, larch
•
Tap root systems – a strong vertical main root descends from the underside of the trunk – English
oak, Scots pine
1
2
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3
These sheets have been designed to be shared. Feel free to photocopy and provide to colleagues.
The Woodland Trust is the UK’s leading woodland conservation charity dedicated to the protection
of our native woodland heritage. www.woodlandtrust.org.uk www.AncientTreeHunt.org.uk
CURRICULUM FOR EXCELLENCE Science – Second/Third/Fourth Levels – page 7
The Ancient
Tree Hunt
SCIENCE:
ROOTS FOR SURVIVAL
ACTIVITY SHEET 5/S3: STUDENT SHEET
Ancient tree roots for survival
Write the correct term in the space provided.
3720/06/08
aerial
roots
butress
roots
rooten
wood
These sheets have been designed to be shared. Feel free to photocopy and provide to colleagues.
The Woodland Trust is the UK’s leading woodland conservation charity dedicated to the protection
of our native woodland heritage. www.woodlandtrust.org.uk www.AncientTreeHunt.org.uk
reduced root
system
CURRICULUM FOR EXCELLENCE Science – Second/Third/Fourth Levels – page 8
The Ancient
Tree Hunt
SCIENCE:
ROOTS FOR SURVIVAL
UNIT 5: TEACHERS SHEET
Equipment needed:
Activity 3:
Investigating root tips
Copies of Student Information Sheet 5/S4 Plant Cells
and Root hair cells – one each
What to do
Copy of how to run the adaptation of the activity Build aTree
– see the website: www.fungi4schools.org/GBF_web/
Activity_Leaders_Notes.htm Click on Build a Tree
Recap the main purposes of the root system for ancient trees
and trees generally – water, mineral/nutrient absorption
and transport and physical support. Ask how they think
water and nutrients are absorbed from the soil – what would
they see happening if they could go underground?
To take up water and nutrients efficiently (and increase
structural support) roots need to establish a close relationship
with the surrounding soil. This is achieved by developing a
mass of fine roots and root hairs, that significantly increase the
surface area of root to soil contact.
Explain how tree roots need oxygen to respire. Most well
drained, loamy, soils will provide oxygen from the air between
the soil particles. Root growth is inhibited if the oxygen level
falls below 10-15%, and stops at less than 5%. This may happen
most often in waterlogged and/or clay soils. Some trees that
are flood tolerant e.g. willows and alder, have strategies to
cope with lower levels of oxygen.
Most of the exchange of water and nutrients takes place
behind the root tip, at a microscopic scale, through root
hairs. These are constantly forming, performing, and dying –
being replaced by new root hairs.
Root hair cells have to be able to absorb large amounts of
water, under the suction effect of the evapo-transpiration
stream, pulling water up to the leaves. This process relies on
diffusion, and the process of absorbing minerals/nutrients
depends on osmosis. Both processes depend on a large
surface area for exchange. Roots will grow vigorously in soils
particularly rich in nitrogen and phosphorus – often in the
upper, organic –rich, soil horizons.
Use standard laboratory demonstrations of these processes to
develop the participants understanding.
Cells to demonstrate and explain the similarities and differences.
They can use the labels to match the features indicated.
Observations by scientists reveal that over 90% of plants have a
fungus associated with their roots, and many would not survive
without them. These mycorrhizal fungi are explored in Unit 3
Ancient trees – hotspots for wildlife and Student Activity
Sheet 3/S4 Know your fungus – what they do.
The filament-like hyphae of these fungi means the surface area
associated with the fungus mycelium, is much greater than that
provided by root hairs. The mycorrhiza’s mycelium provides a
far more efficient means of absorbing water and minerals/
nutrients for the tree. The relationship is mutual, since the
fungi gains food (sugars) directly through the roots. Reinforce
that this is another example of a symbiotic relationship, this
time between plant and fungus.
In order to summarise the role of roots for trees/ancient trees
and help assess the participants understanding of the processes
involved – use the adaptation of the activity Build a Tree – see
the website: www.fungi4schools.org/GBF_web/
Activity_Leaders_Notes.htm. Click on Build a Tree.
Ask the students to add to the original activity by developing a
movement/sound sequence illustrating the stages of wood decay,
recycling of roots, trunks and branches – all wood tissue, through to
the ultimate death of a tree. [You may like to work with the drama
or PE/dance teacher/s in helping students develop their ideas.]
Ask how they view the death of a tree in this context? Is death,
the end for the tree and its impact on the environment? No, it is
only the beginning of a further cycle of life – the recycling of all
the nutrients in its tissues, for use by other organisms.
3720/06/08
Use Student Activity Sheet 5/S4 – Plant Cells and Root Hair
These sheets have been designed to be shared. Feel free to photocopy and provide to colleagues.
The Woodland Trust is the UK’s leading woodland conservation charity dedicated to the protection
of our native woodland heritage. www.woodlandtrust.org.uk www.AncientTreeHunt.org.uk
CURRICULUM FOR EXCELLENCE Science – Second/Third/Fourth Levels – page 9
The Ancient
Tree Hunt
SCIENCE:
ROOTS FOR SURVIVAL
ACTIVITY SHEET 5/S1: STUDENT SHEET (1 of 2)
Plant Cells and Plant Root Cells – tell the difference
Match the labels (Activity sheet 5/S1: Student sheet 2 of 2) to the diagram
PLANT CELLS
Plant cells that take part in photosynthesis (making sugars [plant food] from oxygen, carbon dioxide and water)
require chlorophyll to fix the sunlight energy to power the process.The cell chloroplasts contain the chlorophyll.
PLANT ROOT CELLS
Root hair cells absorb water through the process of diffusion. The rate of diffusion is directly proportional
to the surface area. The root cells directly contacting the soil elongate to form ‘root hairs’.
3720/06/08
water and
nutrients
absorbed by
diffusion
and osmosis
These sheets have been designed to be shared. Feel free to photocopy and provide to colleagues.
The Woodland Trust is the UK’s leading woodland conservation charity dedicated to the protection
of our native woodland heritage. www.woodlandtrust.org.uk www.AncientTreeHunt.org.uk
CURRICULUM FOR EXCELLENCE Science – Second/Third/Fourth Levels – page 10
The Ancient
Tree Hunt
SCIENCE:
ROOTS FOR SURVIVAL
ACTIVITY SHEET 5/S1: STUDENT SHEET (2 of 2)
Plant Cells and Plant Root Cells – tell the difference
Match the labels to the diagram (Activity sheet 5/S1: Student sheet 1 of 2)
PLANT CELLS
Cell wall of cellulose
Cell membrane
Nucleus
Vacuole
Chloroplast
Cytoplasm
Mitochondria
PLANT ROOT CELLS
Root hair cell
Root cell
Xylem vessels taking water
Cytoplasm
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Vacuole
These sheets have been designed to be shared. Feel free to photocopy and provide to colleagues.
The Woodland Trust is the UK’s leading woodland conservation charity dedicated to the protection
of our native woodland heritage. www.woodlandtrust.org.uk www.AncientTreeHunt.org.uk
CURRICULUM FOR EXCELLENCE Science – Second/Third/Fourth Levels – page 11
The Ancient
Tree Hunt
SCIENCE:
ROOTS FOR SURVIVAL
ACTIVITY SHEET 5/S1: TEACHER SHEET (ANSWERS)
Plant Cells and Plant Root Cells – tell the difference
Match the labels (Activity sheet 5/S1: Student sheet 2 of 2) to the diagram
PLANT CELLS
Plant cells that take part in photosynthesis (making sugars [plant food] from oxygen, carbon dioxide and water)
require chlorophyll to fix the sunlight energy to power the process.The cell chloroplasts contain the chlorophyll.
Cytoplasm
Vacuole
Cell wall of cellulose
Mitochondria
Cell membrane
Chloroplast
nucleus
PLANT ROOT CELLS
Root hair cells absorb water through the process of diffusion. The rate of diffusion is directly proportional
to the surface area. The root cells directly contacting the soil elongate to form ‘root hairs’.
Root cell
Root hair cell
water and
nutrients
absorbed by
diffusion
and osmosis
Xylem vessels taking water
Vacuole
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Cytoplasm
These sheets have been designed to be shared. Feel free to photocopy and provide to colleagues.
The Woodland Trust is the UK’s leading woodland conservation charity dedicated to the protection
of our native woodland heritage. www.woodlandtrust.org.uk www.AncientTreeHunt.org.uk