ISA Tree Selection and Planting 3

Question 1

How long does a transplanted tree typically require to fully establish in a new planting site?

Accepted Answer

Approximately one year per inch of trunk diameter

Answer

The accepted guideline is approximately one year of establishment time per inch of trunk caliper, meaning larger trees require proportionally longer establishment periods.

Question 2

Tree support stakes installed at the time of planting should generally be removed:

Accepted Answer

Once the tree can stand upright without support, typically within 1–2 years

Answer

Stakes should be removed as soon as the tree can stand independently because long-term staking prevents the development of trunk taper and structural wood strength.

Question 3

Supplemental irrigation for a newly planted tree can MOST appropriately be reduced when:

Accepted Answer

Roots have expanded well beyond the original root ball into native soil

Answer

Once roots have extended into the surrounding native soil, the tree has access to a much larger water reservoir and irrigation frequency can safely be reduced.

Question 4

Fertilization of a newly planted tree is MOST appropriate:

Accepted Answer

After at least one full growing season of establishment

Answer

Fertilizing before establishment can cause salt stress and root injury; waiting until the root system is established prevents these risks.

Question 5

Which irrigation approach is MOST effective at promoting establishment in newly planted trees?

Accepted Answer

Slow, deep watering that wets the entire root zone

Answer

Slow, deep watering wets the full root zone and encourages roots to grow deep into the soil profile, promoting greater stability and drought resistance.

(ISA) ISA Certified Arborist Practice Test

(ISA) ISA Certified Arborist Practice Test

ISA Tree Selection and Planting 3