ISA ARBORIST CERTIFICATION EXAM COMPLETE QUESTIONS AND VERIFIED
SOLUTIONS LATEST UPDATE
1. Phelloderm - ANSWER In the stems of woody plants, a thin layer of cells located
between the outer cork cells and inner cork cambium.
2. cork cambium - ANSWER Lateral meristematic tissue that produces the outer covering of
stems
3. lenticles - ANSWER opening in bark of woody stem, allows air to enter stem to provide
respiration
4. internode - ANSWER A segment of a plant stem between the points where leaves are
attached.
5. lateral bud - ANSWER meristematic area on the side of a stem that gives rise to side
branches
6. leaf scar - ANSWER a scar on a stem where a leaf has been attached in a previous year
7. terminal bud scale scars - ANSWER the scars left when the bud scales dropped off in the
spring
8. auxin - ANSWER a plant hormone that promotes root formation and bud growth
9. cuticle - ANSWER A waxy covering on the surface of stems and leaves that acts as an
adaptation to prevent desiccation in terrestrial plants.
10. petiole - ANSWER the stalk of a leaf
,11. ray - ANSWER cells that cross the phloem and xylem for radial transport
12. Eudicots - ANSWER Member of a clade consisting of the vast majority of flowering
plants that have two embryonic seed leaves, or cotyledons.
13. Monocot - ANSWER An angiosperm that has only one seed leaf.
14. whorled leaf arrangement - ANSWER three or more leaves per node
15. petiolule - ANSWER the stalk of a leaflet
16. specific epithet - ANSWER The second part of a binomial, it refers to one species within
a genus.
17. Micropores - ANSWER are fine soil pores, typically a fraction of a millimeter in
diameter. They are responsible for a soil's water-holding capacity. Like the fine pores in a
sponge or towel, micropores hold water against the force of gravity. Much of the water
held in micropores is available to plants, but some is held so tightly that plant roots
cannot use it.
18. Macropores - ANSWER are large soil pores, usually between aggregates, that are
generally greater than 0.08 mm in diameter. Macropores drain freely by gravity and allow
easy movement of water and air. They provide habitat for soil organisms and plant roots
can grow into them.
19. sodic - ANSWER Containing excessive amounts of sodium
20. Rhizosphere - ANSWER The soil region close to plant roots and characterized by a high
level of microbiological activity.
, 21. gravitational water - ANSWER Drains out of pore spaces after a rain
22. field capacity - ANSWER ability of a soil to hold water against the downward pull of
gravity
23. Water holding capacity - ANSWER how well soil can retain water (sand is low, clay is
high)
24. tensiometer - ANSWER instrument used to measure soil moisture
25. Soil aggregates - ANSWER Soil particles that are closely bound together are called peds
or aggregates
26. bulk density - ANSWER mass of dry soil
27. buffering capacity - ANSWER the ability of a substance to resist changes in pH
28. root exudates - ANSWER organic compounds, such as amino acids, enzymes, and
carbohydrates, that are secreted by plant roots into the surrounding soil
29. Nitrogen Mineralization - ANSWER the conversion of an element from an organic state
(biomass, SOM) to an inorganic state that plants can uptake.
30. capillary water - ANSWER Water that clings in the micropores when at field capacity or
lower
31. structural soils - ANSWER Soils designed to meet compaction requirements along with
allowing root growth. engineered soils
SOLUTIONS LATEST UPDATE
1. Phelloderm - ANSWER In the stems of woody plants, a thin layer of cells located
between the outer cork cells and inner cork cambium.
2. cork cambium - ANSWER Lateral meristematic tissue that produces the outer covering of
stems
3. lenticles - ANSWER opening in bark of woody stem, allows air to enter stem to provide
respiration
4. internode - ANSWER A segment of a plant stem between the points where leaves are
attached.
5. lateral bud - ANSWER meristematic area on the side of a stem that gives rise to side
branches
6. leaf scar - ANSWER a scar on a stem where a leaf has been attached in a previous year
7. terminal bud scale scars - ANSWER the scars left when the bud scales dropped off in the
spring
8. auxin - ANSWER a plant hormone that promotes root formation and bud growth
9. cuticle - ANSWER A waxy covering on the surface of stems and leaves that acts as an
adaptation to prevent desiccation in terrestrial plants.
10. petiole - ANSWER the stalk of a leaf
,11. ray - ANSWER cells that cross the phloem and xylem for radial transport
12. Eudicots - ANSWER Member of a clade consisting of the vast majority of flowering
plants that have two embryonic seed leaves, or cotyledons.
13. Monocot - ANSWER An angiosperm that has only one seed leaf.
14. whorled leaf arrangement - ANSWER three or more leaves per node
15. petiolule - ANSWER the stalk of a leaflet
16. specific epithet - ANSWER The second part of a binomial, it refers to one species within
a genus.
17. Micropores - ANSWER are fine soil pores, typically a fraction of a millimeter in
diameter. They are responsible for a soil's water-holding capacity. Like the fine pores in a
sponge or towel, micropores hold water against the force of gravity. Much of the water
held in micropores is available to plants, but some is held so tightly that plant roots
cannot use it.
18. Macropores - ANSWER are large soil pores, usually between aggregates, that are
generally greater than 0.08 mm in diameter. Macropores drain freely by gravity and allow
easy movement of water and air. They provide habitat for soil organisms and plant roots
can grow into them.
19. sodic - ANSWER Containing excessive amounts of sodium
20. Rhizosphere - ANSWER The soil region close to plant roots and characterized by a high
level of microbiological activity.
, 21. gravitational water - ANSWER Drains out of pore spaces after a rain
22. field capacity - ANSWER ability of a soil to hold water against the downward pull of
gravity
23. Water holding capacity - ANSWER how well soil can retain water (sand is low, clay is
high)
24. tensiometer - ANSWER instrument used to measure soil moisture
25. Soil aggregates - ANSWER Soil particles that are closely bound together are called peds
or aggregates
26. bulk density - ANSWER mass of dry soil
27. buffering capacity - ANSWER the ability of a substance to resist changes in pH
28. root exudates - ANSWER organic compounds, such as amino acids, enzymes, and
carbohydrates, that are secreted by plant roots into the surrounding soil
29. Nitrogen Mineralization - ANSWER the conversion of an element from an organic state
(biomass, SOM) to an inorganic state that plants can uptake.
30. capillary water - ANSWER Water that clings in the micropores when at field capacity or
lower
31. structural soils - ANSWER Soils designed to meet compaction requirements along with
allowing root growth. engineered soils
