Colorado Master Gardener Training

Pruning Cuts

The Art of Pruning

Size and shape control

The Science

of Pruning

Why: Structure & Plant health

How: Natural target pruning

The Art of PruningPruning to Control Shape

The Art of PruningPruning to Control Shape

Branch grows in direction of bud.

The Science of Pruning: Prune with purpose in mind.

How plants respond to woundsNatural Target PruningTypes of pruning cuts

Pruning standards Deciduous trees

New plantingTraining young treesMature treesSpecial need

EvergreensShrubs

Tree physiology

A tree is a series of boxes or “compartments” framed by annual growth rings and rays.

Each “compartment” is filled with tubes (xylem tissue) that transmit water and nutrients up into the tree.

Trees don’t heal, they seal.

Trees don’t heal, they seal.

CODITCompartmentalizatio

n of Decay In Trees

Reaction ZoneChemical change in

cells seal-off or “compartmentalize” the area

Trees don’t heal, they seal.

CODITCompartmentalizatio

n of Decay In Trees

Reaction ZoneChemical change in

cells seal-off or “compartmentalize” the area

CODIT on old Cottonwood trunk

Reaction Zone(Reaction Wood)

CODITCompartmentalization Of Decay In Trees

Reaction Zone

Microorganism Area

Decayed wood

Branch Collar

Branch Bark Ridge

Branch Defense ZoneA ring of cells responsible for Woundwood growth and active in the reaction wood process.

Woundwood closing over pruning cut

Branch collar

Branch defense zone cells

For the Branch Defense Zone to be active, the side branch must be less than 1/2 the diameter of the trunk/parent branch.

Less than 1/3 is preferred.

Natural Target PruningProtects the Branch Defense Zone.

branch bark ridge

branch collar

branch collar

final cut

Terms

CODIT

Reaction Zone

Branch Collar

Branch Defense Zone

Type of pruning cut impacts Ability to defend against decay Regrowth

Natural target pruning cutsRemove side branch back to

larger parent branch/trunk.

Reduction cutsRemove larger branch back to

smaller side branch.

Heading cutsRemove branch tip

1. Preserves the branch defense zone

2. Thins branching pattern Increases sunlight penetration

into plant’s interior

Increases air circulation

3. Only minor influence on height

Natural target pruning cuts remove a smaller side branch back to trunk/parent branch.

Natural Target PruningProtects the Branch Defense Zone.

branch bark ridge

branch collar

branch collar

final cut

Natural target pruning cuts: Use caution to not nick or injure the branch bark ridge.

With proper cut, Woundwood grows over pruning wound

Pruning cut nicked branch bark ridge on bottom. Note how woundwood fails to grow in this area.

Ash Aspen

Natural Target Pruning on Conifers

branch bark ridge

branch collar

final cut

branch collar

Quality of pruning cut?

Reduction cuts remove a larger branch back to a smaller side branch.

NO branch defense zone

Thins branching pattern

Lowers height

Final Cut

Reduction cuts: Angle of final cut splits difference between angle of branch bark ridge and angle perpendicular to branch being removed.

Angle perpendicular to branch being removed

Angle of FINAL CUT

Angle of branch bark ridge

Branch bark ridge

Reduction cuts: To prevent suckering, the smaller branch should be at least 1/3 the diameter of larger branch removed. (At least 1/2 the diameter is preferred.)

Final Cut

Heading cuts make the branch bushier.

Removes the hormone auxinin shoot’s growing tip.

Releases lateral sidebuds

to grow.

Branching at point of pruning gives a bushier plant.

Decreases sunlight intoplant’s interior.

Natural Target Pruning (thinning) Cut

Reduction Cut

Heading Cut

3 cut method for any limb larger than 1”

1. Undercut limb, 12-15” out from crotch.

2. Moving out a couple of inches from 1st, make second cut from top removing limb.

3. Make final cut with Natural Target Pruning techniques.

3 cut method for any limb larger than 1”

Dead limb removal