Certified Arborist Test Tree Pruning Principles 2

Question 1

What is the branch protection zone (BPZ) and why is it critical to identify before making a pruning cut?

Accepted Answer

The zone of chemically and anatomically distinct tissue at the branch base that resists decay spread

Answer

The branch protection zone is a chemically distinct zone of tissue at the branch base containing defensive compounds that resist decay spread into the parent stem — pruning cuts must be made just outside this zone to preserve these defenses.

Question 2

What is the recommended sequence of cuts when removing a large limb to prevent bark tearing?

Accepted Answer

Undercut first to prevent bark stripping, then top cut, then final cut just outside branch collar

Answer

The three-cut method prevents bark tearing: (1) a partial undercut on the underside of the limb 12-18 inches from the trunk, (2) a top cut further out from the trunk to remove the bulk of the limb, allowing the stub to fall without stripping bark, and (3) the final cut just outside the branch collar.

Question 3

What is the primary purpose of crown raising, and what is the minimum acceptable live crown ratio after raising?

Accepted Answer

Removing lower branches to provide clearance — maintaining at least 40-60% live crown ratio for tree health

Answer

Crown raising removes lower branches to provide clearance for vehicles, pedestrians, or buildings. ISA guidelines recommend maintaining a live crown ratio of at least 40% (some recommend 60% for young trees) to preserve adequate photosynthetic capacity and structural taper.

Question 4

What distinguishes 'topping' from proper reduction pruning, and why is topping considered harmful?

Accepted Answer

Topping cuts branches back to stubs or laterals too small to assume the terminal role; proper reduction maintains lateral size ratios

Answer

Topping makes random heading cuts to arbitrary stubs, leaving large wounds with no lateral to assume dominance, triggering epicormic sprout production and decay. Proper crown reduction cuts back to laterals at least one-third the diameter of the removed stem, maintaining structure and natural form.

Question 5

When is wound dressing (pruning paint/sealant) recommended after pruning cuts, according to current ISA guidelines?

Accepted Answer

After pruning cuts on oak trees to prevent nitidulid beetle vectors of oak wilt from entering fresh cuts

Answer

Current ISA guidelines state that wound dressings do not benefit most trees — they neither prevent decay nor accelerate wound closure. The primary exception is oak trees pruned in areas with oak wilt, where wound dressings may reduce the risk of sap-feeding nitidulid beetles (vectors of Ceratocystis fagacearum) being attracted to fresh wounds.

Certified Arborist Test Practice Test

Certified Arborist Test Practice Test

Certified Arborist Test Tree Pruning Principles 2