ISA Arborist Certification Training Chapter 8 - Pruning

Illinois Arborist Association Arborist Certification Training

September 1, 2015

Presented by: Ben Reynoso & Eva Saunders Introduction Pruning is one of the most common procedures carried out on a tree. If done correctly, it can improve tree structure, health and longevity. Pruning Standards Many countries have developed standards for pruning. In the United States, the American National Standards Institute (ANSI) has developed tree care standards in conjunction with green industry. v ANSI A300 – This series covers a range of arboricultural activities. (Planting, support systems, risk assessments, etc.) Pruning was the first one created. v ANSI Z133 – Covers safety when working around trees. Pruning Objectives v Reduce potential for tree or branch failure v Clearance v Reducing wind resistance v Maintain tree health v Influence fruiting or flowering v Improve a view v Improve aesthetics Branch Attachment

To understand the affect of pruning on the tree, we must understand the details of the branch structure where cuts may occur Timing

 Dormant Season

 Bloom on current season growth – prune in winter prior to leaf emergence (Albizia and Golden Raintree)

 Bloom on last season growth – prune just after bloom (Serviceberry, Crabapple, & Redbud) Pruning Cuts

1. Cut 1 - Undercut the limb. 2. Cut 2 - Removes the limb. 3. Cut 3 - Final cut just outside branch collar removes the stub. Structural Pruning of Young Trees

1. Remove broken, dead, dying, or damaged branches. 2. Establish a dominant leader. 3. Select and establish the lowest permanent branch. 4. Select and establish scaffold branches 5. Select and subordinate temporary branches

Photo Credits: Natural Path Urban Forestry, 2014 Pruning Techniques v Cleaning v Thinning v Raising v Reduction v Restoration Photo Credits: Natural Path Urban Forestry, 2014 v Utility Pruning Pruning Techniques

Cleaning is the pruning of dead, damaged, and diseased branches. It is the most common tree pruning type arborists perform. Pruning Techniques

Thinning: is the selective removal of branches in the interior of the crown to increase light penetration and reduce sail effect. Pruning Techniques

Raising: removes the lower branches of a tree in order to provide clearance for buildings, sign, vehicles, pedestrians and line of sight. Pruning Techniques

Reduction: is a technique to reduce the size of a tree for utility clearance or trees going through retrenchment. Pruning Techniques

Restoration:

is a technique to repair a tree that has experienced significant damage, either from a storm, topping or utility clearance. Pruning Techniques

Utility Pruning: is the removal of branches to prevent the loss of service, damage to utility equipment and to provide access. Why Not to Top v Loss of photosynthetic leaf area v Insects and disease issues increase v Future weak attachments created v Rapid new growth v Causes tree death v Poor visual aesthetic v Cost to maintain Pruning Palms Fronds are removed typically when they become unhealthy or dangerous.

Do not prune above horizontal fronds. Specialty Pruning

Espalier – pruning and training branches along one plane

Pollarding – severe heading back with annual removal of sprouts at same point. Plant Growth Regulators

Enhance or alter the growth process of a tree (antigibberellins)