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Roots, Leaves & Seeds
How plants feed, reproduce and survive the year.
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Plants produce their own food through which process?
The Lives of Trees
A tree is mostly dead tissue held up by a thin living layer, which explains a surprising amount about how it grows.
About this topic
Most of a mature tree is not alive. The bulk of the trunk is old wood whose cells died long ago, retained because it is strong and because it once carried water. The living part is a thin sleeve: a layer of dividing cells a few cells thick, adding wood on its inner face and bark on its outer one, year after year. That is why a trunk thickens but a mark cut into it never rises, and why removing a complete ring of bark is fatal. The other surprise is how water gets to the top. There is no pump. Water evaporating from the leaves puts the whole column under tension, and it holds together because water molecules cling to one another strongly enough to be pulled rather than pushed. That mechanism sets a practical ceiling on tree height. Below ground, meanwhile, most trees are in partnership with fungi that extend their reach into the soil in exchange for sugar.
Questions & answers
The Lives of Trees: all 10 questions and answers
Every question in this quiz is listed below with its correct answer and the reasoning behind it. Play first if you would rather not see the answers — or read through as a study sheet.
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1What do the rings visible in a cut tree trunk record?
- A Alternating wet and dry months within a single year
- B One year of growth each, wide in good seasons and narrow in poor ones Correct
- C One ring for every serious drought the tree survived
- D The number of large branches the tree has shed
Answer: B. One year of growth each, wide in good seasons and narrow in poor ones
Why: Matching ring patterns between samples lets dendrochronologists date timber to the exact year, and the method has been used to check and correct radiocarbon dates.
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2Which tissue carries sugars made in the leaves to the rest of a tree?
- A Phloem Correct
- B Xylem
- C Cambium
- D Cork
Answer: A. Phloem
Why: Xylem moves water and dissolved minerals the other way, upward from the roots. Cutting a complete ring of bark severs the phloem and eventually kills the tree.
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3What is heartwood?
- A The living growth layer immediately beneath the bark
- B The soft pith at the centre of a young sapling
- C A hollow left in the trunk by fungal decay
- D Older inner wood that no longer carries sap, often darker and more rot-resistant Correct
Answer: D. Older inner wood that no longer carries sap, often darker and more rot-resistant
Why: Resins and tannins deposited as those cells shut down give it both its colour and its durability, which is why it is the part prized for furniture and boatbuilding.
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4Conifers differ from broadleaved trees chiefly in which respect?
- A They have no true roots, only anchoring structures
- B They cannot reproduce from seed at all
- C They carry their seeds in cones rather than enclosing them in a fruit Correct
- D They never shed any of their leaves
Answer: C. They carry their seeds in cones rather than enclosing them in a fruit
Why: Larches are conifers that drop their needles every autumn, and yews hold each seed in a fleshy red cup instead of a woody cone.
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5What produces the yellow and orange colours of autumn leaves?
- A Strong autumn sunlight bleaches the green pigment
- B Pigments already present in the leaf become visible as the chlorophyll breaks down Correct
- C New pigments are manufactured in response to frost damage
- D Sugars crystallise within the leaf tissue
Answer: B. Pigments already present in the leaf become visible as the chlorophyll breaks down
Why: The reds work differently: many trees synthesise those from scratch in autumn, possibly to shield the leaf while nutrients are drawn back into the twigs.
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6What are mycorrhizae?
- A Fungi living in partnership with tree roots, trading soil minerals for sugars Correct
- B Insects that bore galleries beneath the bark
- C Root nodules that fix nitrogen straight from the air
- D Woody buttresses that anchor a tree against wind
Answer: A. Fungi living in partnership with tree roots, trading soil minerals for sugars
Why: The fungal threads reach far more soil than a root hair can, and the great majority of land plants depend on some version of the arrangement.
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7What does it mean to coppice a tree?
- A To remove the lower branches and raise the crown
- B To graft a second species onto the standing trunk
- C To ring the bark so that the tree dies slowly in place
- D To cut it near ground level so that it regrows several stems from the stump Correct
Answer: D. To cut it near ground level so that it regrows several stems from the stump
Why: Hazel and willow have been managed this way for thousands of years, and a repeatedly cut stool can outlive an untouched tree of the same species.
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8How does water reach the leaves at the top of a tall tree?
- A Cells lift it one at a time by active transport
- B Wind pressure at the crown draws it through the trunk
- C Evaporation from the leaves pulls a continuous column of water upward under tension Correct
- D A pump in the root system pushes it up the trunk
Answer: C. Evaporation from the leaves pulls a continuous column of water upward under tension
Why: The column holds together because water molecules cling to one another, and this transpiration pull sets a practical ceiling on how tall a tree can grow.
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9What is the cambium of a tree?
- A The network of fine feeding roots near the surface
- B A thin layer of dividing cells adding wood on one side and bark on the other Correct
- C The dead outer bark that flakes away
- D The central column of the oldest wood
Answer: B. A thin layer of dividing cells adding wood on one side and bark on the other
Why: It is the reason a trunk thickens outward, and also the reason a nail driven into a trunk stays at exactly the same height for the life of the tree.
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10Aspens and some other trees can form a whole stand consisting of what?
- A Genetically identical stems joined by one shared root system Correct
- B Separate seedlings whose trunks fuse together as they grow
- C Trees sharing a single canopy but no root contact
- D An even mixture of two species that hybridise freely
Answer: A. Genetically identical stems joined by one shared root system
Why: New stems arise as suckers from the roots, so what looks like a wood can be one organism. Fire clears competing species and tends to favour the habit.
Frequently asked questions about The Lives of Trees
How many questions are in The Lives of Trees?
The Lives of Trees has 10 questions and takes about 7 minutes to finish. It is rated Medium and sits in our Plants & Gardening category.
How is The Lives of Trees scored?
Each of the 10 correct answers adds 10 XP, up to 100 XP for a clean run. Wrong answers cost you nothing, and your full question-by-question review is shown at the end.
Are the answers to The Lives of Trees explained?
Yes. All 10 questions carry a written explanation of why the correct answer is right, so the quiz works as a study sheet as well as a test.
Can I replay The Lives of Trees?
Yes, as often as you like. The questions and the answer options are reshuffled on each run, and you can use Practice Mistakes afterwards to retry only the ones you missed. No account is needed to play.
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