Arborist Practice is independent and not affiliated with the International Society of Arboriculture. These are original xylem and phloem practice questions written for study. They are not real ISA exam questions, not official ISA material, and not a substitute for ISA's current exam outline, official study materials, or professional arboricultural judgment.
The short version
ISA Certified Arborist xylem and phloem practice questions test whether you can connect tree tissue to function. Xylem moves water and dissolved minerals from roots toward the crown. Phloem moves sugars and other photosynthates from source tissues, usually leaves, to sinks such as roots, shoots, fruit, wounds, and storage tissues. The cambium produces xylem inward and phloem outward.
Most misses come from swapping those roles. A question may mention drought, girdling, a trunk wound, defoliation, root stress, or a cross-section diagram. The answer depends on the tissue function being tested, not on the most dramatic field detail.
Use this page when your Tree Biology misses involve xylem, phloem, cambium, transpiration, photosynthesis, sapwood, heartwood, source-sink movement, or girdling. For the broader domain, review the tree biology ISA exam guide, then take the free ISA Tree Biology practice questions. If your misses are more about wounds, decay, and barrier zones, use the CODIT practice questions instead.
Where xylem and phloem fit on the exam
ISA lists Tree Biology as one of the Certified Arborist exam domains. Use ISA's current materials as the source of truth for domain wording and official exam policies:
Fresh SERP checks for xylem, phloem, transpiration, and photosynthesis practice queries showed mostly general biology resources such as Quizlet, BBC Bitesize, BYJU'S, TikTok snippets, and school-exam pages. ISA-specific SERPs are thinner. That makes this a useful Arborist Practice repair page: candidates do not need a high-school botany lecture. They need to know how vascular tissue shows up in arborist exam scenarios.
The tissue map to memorize
Draw this from the outside inward before you start the quiz:
| Layer or tissue | Exam-useful job | Common trap |
|---|---|---|
| Bark | Protection | Treating bark as transport tissue |
| Phloem | Moves sugars from sources to sinks | Saying it moves water upward from roots |
| Cambium | Produces new xylem inward and phloem outward | Reversing inward/outward growth |
| Sapwood | Active xylem that conducts water and minerals | Treating all wood as dead support only |
| Heartwood | Older xylem, mainly structural | Saying heartwood conducts most current water flow |
A simple memory rule: water up through xylem, sugars through phloem, new layers from cambium.
How to use this quiz
Treat this as a short repair drill.
- Answer all 12 questions without notes.
- Mark each answer as confident, uncertain, or guessed.
- For every miss, label the error: xylem, phloem, cambium, source-sink movement, transpiration, photosynthesis, sapwood, heartwood, or girdling.
- Write one sentence explaining the tissue function in plain language.
- Retest Tree Biology later with a mixed set so you do not memorize this page.
If you keep choosing the tissue named in the question instead of the tissue that performs the function, slow down. ISA-style questions often include extra tree context, but the tested concept may be direct.
12 xylem and phloem practice questions
1. Water transport
A drought-stressed tree has wilting leaves by late afternoon. The question asks which tissue carries water and dissolved minerals from roots toward the leaves. Which answer is best?
A. Phloem
B. Xylem
C. Outer bark
D. Heartwood only
Best answer: B. Xylem moves water and dissolved minerals upward from roots toward the crown. Phloem moves sugars. Heartwood is older xylem with mostly structural function, not the main active transport path.
2. Sugar movement from leaves
Leaves in the upper crown produce carbohydrates during photosynthesis. Which tissue moves much of that sugar to roots, shoots, storage tissues, and other sinks?
A. Phloem
B. Sapwood xylem
C. Bark scales
D. Pith
Best answer: A. Phloem transports photosynthates from source tissues to sink tissues. In many questions, "sugars," "carbohydrates," "photosynthates," or "source and sink" point to phloem.
3. Cambium growth direction
During secondary growth, what does the vascular cambium produce?
A. Xylem inward and phloem outward
B. Phloem inward and xylem outward
C. Bark inward and roots outward
D. Heartwood outward and leaves inward
Best answer: A. The cambium is a thin layer of dividing cells. It produces new xylem to the inside and new phloem to the outside. Reversing this order causes many cross-section questions to fall apart.
4. Girdling injury
A continuous mower wound removes bark and phloem around the circumference of a young tree, but much of the sapwood is still intact. What is the main long-term problem?
A. Water immediately stops moving in all xylem
B. Sugars cannot move normally through the phloem to roots and other sinks
C. Heartwood begins producing leaves
D. Transpiration becomes photosynthesis
Best answer: B. Girdling interrupts phloem transport. Water may still move in xylem for a while, so the tree can look alive before root starvation and decline become obvious.
5. Sapwood vs heartwood
Which statement best separates sapwood from heartwood?
A. Sapwood is active xylem involved in water movement; heartwood is older xylem used mainly for support
B. Sapwood is living phloem; heartwood is outer bark
C. Sapwood conducts sugars downward; heartwood conducts all current water upward
D. Sapwood exists only in leaves
Best answer: A. Sapwood is the younger, active xylem. Heartwood is older xylem with reduced or absent conductive function. The exam can test this directly or hide it inside wound and decay scenarios.
6. Transpiration clue
A question describes water loss from leaves through stomata and the pull that helps move water upward through the tree. Which process is being described?
A. Transpiration
B. Photosynthesis
C. Compartmentalization
D. Phloem loading only
Best answer: A. Transpiration is water vapor loss from leaves. It helps drive the upward movement of water through xylem. Photosynthesis makes sugars; it does not describe water vapor loss.
7. Photosynthesis clue
A question asks which process uses light energy to produce sugars in leaves. Which answer is best?
A. Photosynthesis
B. Transpiration
C. Girdling
D. Decay compartmentalization
Best answer: A. Photosynthesis produces sugars. After production, those sugars move through phloem to sinks. Do not blend the sugar-making process with the water-movement process.
8. Source and sink wording
A tree flushes new shoot growth in spring. Stored carbohydrates and current photosynthates move toward growing tissues. In source-sink language, the growing shoots are best described as what?
A. Sinks using imported carbohydrates
B. Heartwood converting into bark
C. Xylem producing sugars
D. Dead tissue with no resource demand
Best answer: A. A sink is a tissue or organ using or storing carbohydrates. Growing shoots, roots, fruit, callus tissue, and storage organs can act as sinks depending on season and tree condition.
9. Cross-section order
In a trunk cross-section, which order is most useful for exam questions when moving from outside toward the center?
A. Bark, phloem, cambium, xylem
B. Xylem, bark, phloem, cambium
C. Phloem, heartwood, bark, cambium
D. Roots, leaves, bark, flowers
Best answer: A. Bark is outside. Phloem sits just inside the bark. Cambium separates phloem from xylem and produces new tissue. Xylem lies to the inside.
10. Defoliation and carbohydrate supply
A tree loses most of its leaves early in the growing season. Which tissue-function issue is most directly affected first?
A. Reduced photosynthesis and less sugar available for phloem transport
B. Immediate conversion of xylem into flowers
C. Heartwood becoming the main sugar source
D. Bark producing all new water
Best answer: A. Leaves make sugars through photosynthesis. Heavy defoliation can reduce carbohydrate production and phloem supply to sinks. It does not turn xylem or bark into sugar-making tissue.
11. Root damage and water uptake
Construction cuts a large share of absorbing roots. Soon after, the canopy wilts during hot weather. Which tissue pathway connects the root loss to the canopy symptom?
A. Less water uptake feeding the xylem stream
B. More sugar movement through bark scales
C. More heartwood photosynthesis
D. Phloem replacing all lost roots
Best answer: A. Absorbing roots take up water and minerals that move through xylem. Root loss can show as canopy water stress, especially in heat, drought, or compacted soil.
12. Best repair habit
A candidate keeps missing vascular-tissue questions because every answer choice uses a real tree term. What is the best review habit?
A. Ask what substance is moving, where it is moving, and which tissue performs that job
B. Pick the longest botanical word
C. Choose phloem whenever bark is mentioned
D. Ignore the function and memorize answer letters
Best answer: A. Function beats word recognition. Water and minerals point to xylem. Sugars and photosynthates point to phloem. New xylem and phloem production points to cambium.
Score guide
Use the score to choose your next repair block:
- 10-12 correct: Vascular tissue reasoning is probably stable. Review guessed items, then move to CODIT, pruning cuts, or mixed Tree Biology questions.
- 7-9 correct: You know some terms but still swap functions. Redraw the tissue map and write what each layer does before taking another set.
- 0-6 correct: Stop mixed mocks for now. Relearn xylem, phloem, cambium, sapwood, heartwood, transpiration, photosynthesis, and source-sink movement before retesting.
This score is not an exam prediction. It tells you whether tissue-function questions are still costing you avoidable points.
What to study after this drill
Use your misses to choose the next page:
| If you missed | Study next |
|---|---|
| Broad Tree Biology vocabulary | Tree biology ISA exam guide |
| Mixed Tree Biology practice | Free ISA Tree Biology practice questions |
| Photosynthesis, respiration, transpiration, stomata, or leaf water loss | Photosynthesis and transpiration practice questions |
| Wounds, decay, Wall 4, or branch collars | CODIT practice questions |
| Cut placement, branch collars, reduction, or heading | Pruning cuts practice questions |
| Root stress, fine roots, mycorrhizae, oxygen, compaction, or water uptake | Root function and mycorrhizae practice questions, soil texture and drainage practice questions |
| Domain-by-domain repair planning | ISA Certified Arborist domain practice questions hub |
When the tissue roles are stable, confirm them inside a timed mixed set or the ISA Certified Arborist exam simulator. Tree Biology often shows up as a hidden subskill inside pruning, diagnosis, construction, and risk questions.
How Arborist Practice fits
Use Arborist Practice to turn vascular-tissue misses into a feedback loop:
- Take a short Tree Biology set.
- Tag misses as xylem, phloem, cambium, CODIT, branch anatomy, or physiology.
- Bookmark questions where the field scenario distracted you from the tissue function.
- Ask the AI tutor to compare close answer choices, especially xylem vs phloem and transpiration vs photosynthesis.
- Retest in mixed practice after the same trap stops repeating.
Arborist Practice uses original practice questions, timed mock exams, explanations, bookmarks, glossary support, AI tutor follow-up, and study analytics. Use official ISA materials for credential rules, exam policies, and current domain wording.
FAQ
Are these real ISA xylem and phloem questions?
No. They are original study questions written for practice. They are not official ISA questions, not copied exam questions, and not a leaked answer bank.
What is the easiest way to remember xylem vs phloem?
Xylem moves water and dissolved minerals from roots toward the crown. Phloem moves sugars and other photosynthates from sources to sinks. If the question asks what is moving, the tissue choice usually becomes clear.
Is transpiration the same as photosynthesis?
No. Transpiration is water vapor loss from leaves and helps pull water through xylem. Photosynthesis uses light energy to produce sugars in leaves. The exam may put both words in one question because candidates often blend them.
Why does girdling hurt a tree if xylem is still intact?
Girdling damages or removes phloem. Water may still move upward through xylem for a while, but sugar movement to roots and other sinks is disrupted. That is why girdled trees can decline after a delay.
Should I study xylem and phloem separately from CODIT?
Yes, if you keep swapping tissue functions. CODIT explains wound response and decay barriers. Xylem and phloem explain transport. Both belong in Tree Biology, but the repair drill is different.