ISA Tree Selection and Planting 2 — Questions and Answers
Question 1: What is the MOST critical step when planting a balled-and-burlapped (B&B) tree?
- Removing all wooden stakes before backfilling
- Locating the root flare and planting at the correct depth (Correct answer)
- Adding a complete fertilizer to the planting hole
- Scoring the sides of the planting hole to promote drainage
Correct answer: Locating the root flare and planting at the correct depth
Planting with the root flare at or slightly above grade is the most critical step; planting too deep leads to stem girdling, anaerobic conditions, and eventual tree death.
Question 2: What is the recommended width of the planting hole for a new tree installation?
- Equal to the diameter of the root ball
- Two to three times the diameter of the root ball (Correct answer)
- One foot wider than the root ball on all sides
- Deep and narrow to anchor and stabilize the tree
Correct answer: Two to three times the diameter of the root ball
A wide planting hole (2–3× the root ball diameter) loosens surrounding soil and allows roots to expand laterally with less resistance.
Question 3: After placing a balled-and-burlapped tree in the planting hole, the wire basket and burlap should be:
- Left completely intact to preserve root ball integrity
- Removed entirely before the tree is set in the hole
- Cut away from the top third of the root ball after the tree is positioned (Correct answer)
- Buried as they will decompose within one growing season
Correct answer: Cut away from the top third of the root ball after the tree is positioned
The top portion of the wire basket and burlap should be cut away after placement to prevent girdling and allow uninhibited root expansion.
Question 4: When planting container-grown trees, circling or girdling roots should be:
- Left intact to avoid unnecessary root disturbance
- Straightened, redirected, or removed before planting (Correct answer)
- Cut flush with the outer edge of the root ball
- Buried deeply to encourage downward redirection
Correct answer: Straightened, redirected, or removed before planting
Circling roots will continue to enlarge and can eventually girdle and kill the tree; they must be corrected at the time of planting.
Question 5: What is the recommended mulch depth when mulching around a newly planted tree?
- 1–2 inches
- 2–4 inches (Correct answer)
- 6–8 inches
- 10–12 inches
Correct answer: 2–4 inches
A 2–4 inch layer of mulch conserves moisture, moderates soil temperature, and suppresses weeds without causing crown rot or oxygen deprivation.
Question 6: The graft union on a grafted nursery tree should be positioned at planting so it is:
- Below the soil surface to encourage scion rooting
- At or slightly above the finished soil grade (Correct answer)
- Surrounded by moist mulch for protection
- Wrapped with tree tape until established
Correct answer: At or slightly above the finished soil grade
The graft union must remain above soil level to prevent the scion from rooting and to preserve the intended rootstock characteristics.
Question 7: What is the PRIMARY purpose of creating a temporary watering berm (ring) around a newly planted tree?
- To prevent foot traffic from compacting the root zone
- To direct irrigation water to the root ball and reduce runoff (Correct answer)
- To protect surface roots from frost damage in winter
- To prevent soil erosion during heavy rain events
Correct answer: To direct irrigation water to the root ball and reduce runoff
A watering berm forms a basin that concentrates irrigation water directly over the root ball where it is most needed during the establishment period.
ISA Tree Selection and Planting 2
What is the MOST critical step when planting a balled-and-burlapped (B&B) tree?