Certified Arborist Test Soil Science and Root Management 1

Question 1

Which soil texture has the smallest individual particle size and tends to retain the most water but drains poorly?

Accepted Answer

Clay

Answer

Sand

Answer

Silt

Answer

Loam

Question 2

What is the primary purpose of a soil percolation test in arboriculture?

Accepted Answer

To determine the rate at which water drains through the soil profile

Answer

To measure the pH level of the soil

Answer

To identify the presence of mycorrhizal fungi

Answer

To assess the nitrogen content available to tree roots

Question 3

What is the critical root zone (CRZ) of a tree generally defined as?

Accepted Answer

A circular area with a radius of 1 foot per inch of trunk diameter

Answer

The area directly beneath the tree's canopy drip line only

Answer

The area within 3 feet of the base of the trunk in all directions

Answer

The zone extending to twice the height of the tree

Question 4

Which of the following best describes a 'soil horizon'?

Accepted Answer

A distinct layer within a soil profile that differs in physical or chemical properties from adjacent layers

Answer

The depth at which roots stop growing due to lack of oxygen

Answer

The boundary between clay and sandy soils at a construction site

Answer

The zone of highest microbial activity around tree feeder roots

Question 5

What does soil pH primarily affect in the context of tree nutrition?

Accepted Answer

The availability of nutrients to tree roots

Answer

The physical structure and aggregate stability of the soil

Answer

The rate at which organic matter decomposes in the root zone

Answer

The depth to which feeder roots can penetrate

Question 6

What is 'girdling root' and what is its primary threat to tree health?

Accepted Answer

A root that encircles the trunk or another root, restricting vascular flow

Answer

A root that grows straight down, competing with the taproot for water

Answer

A surface root that is repeatedly severed by lawn maintenance equipment

Answer

A root that grows into a drain pipe and causes soil subsidence