Certified Arborist Test Trees and Construction 2

Question 1

What is the Critical Root Zone (CRZ) and how is it typically calculated?

Accepted Answer

A circular area around the trunk; typically 1 foot of radius per inch of trunk diameter

Answer

The CRZ is typically calculated as 1 foot of radius for each inch of trunk diameter at breast height (DBH). This area contains the most critical structural and absorbing roots.

Question 2

What is the most common cause of tree death during construction?

Accepted Answer

Root damage from excavation, grade changes, and soil compaction

Answer

Root damage is the #1 killer. Construction activities sever roots through trenching, suffocate them through soil compaction and grade changes, and alter drainage patterns.

Question 3

How does soil compaction from construction equipment harm trees?

Accepted Answer

It reduces soil pore space, limiting oxygen and water availability to roots

Answer

Heavy equipment compresses soil, collapsing the pore spaces that hold air and water. Roots need oxygen to function; compacted soil can effectively suffocate the root system.

Question 4

What type of barrier is most effective for protecting trees during construction?

Accepted Answer

Chain-link or sturdy wooden fencing installed at the drip line or CRZ

Answer

Sturdy physical barriers (chain-link or wood fencing) at the CRZ or drip line are the most effective protection. They physically prevent equipment and material storage from entering the root zone.

Question 5

A builder needs to trench through a tree's root zone for a utility line. What is the preferred alternative method?

Accepted Answer

Use directional boring (tunneling) to go under the root system

Answer

Directional boring (horizontal directional drilling) tunnels beneath the root zone without disturbing roots or soil. This is the preferred method when utilities must pass through a CRZ.

Certified Arborist Test Practice Test

Certified Arborist Test Practice Test

Certified Arborist Test Trees and Construction 2