Pruning Workshop Notes

January 30, 2020
Presented by Randy Overstreet, Arborist with the City of Laramie

Tools:
-Bypass pruners (also known as secateurs); save anvil-style pruners for removing dead wood
-Pruning saws (including folding types; Corona & Silky are brands that Randy mentioned)
-Pole saw

Other Equipment:
Disinfectant spray and a rag to sanitize the cutting blades (Randy uses Lysol spray; 10% bleach is another possibility or at least 70% alcohol)

Decide which branches/limbs need to be pruned:
-those that obstruct a walkway, alley, or city street (city code requires an 8-foot clearance above a city sidewalk and a 13-foot clearance above a city street and alley) or limbs that are too close to a building. Leave power line and other aerial utility line clearance to professionals. If you must leave the ground to prune by climbing or using a ladder, leave the high pruning to professionals.
-those that are diseased or dead
-those that are crossing or will cross other branches (rubbing branches can lead to open wounds that lead to disease)
-water shoots (which originate from just under the bark and are weakly attached; they often grow vertically)

When considering branches/limbs to be removed:
-Think about the longer-term growth of that branch (i.e., will it end up being a problem in a few years).
-Consider how the tree will look after the branch is removed.
-Consider which branch is the dominant leader and maintain this branch as the highest branch to keep the shape of the tree. (See this website or more information about maintaining a dominant leader on trees.)
-Remember that the sum of the removed growth should not be greater than 25% of the tree. If a major overhaul is needed, spread out the pruning over a 3-year period.
-If a choice needs to be made, preserve the limb with a stronger junction (i.e., more obtuse angle) where the limb meets the trunk.

How to make pruning cuts on smaller branches:
-Disinfect your blades before you begin pruning.
-Position the bypass pruner so that the cutting edge is toward the trunk (or older branch) side of the cut. This will make for a cleaner cut on the remaining wood surface, rather than a crushing cut.
-Align the bypass pruner just outside the slight swelling where the branch joins a larger branch or trunk (i.e., the branch collar). When left intact, the branch collar will grow over and cover the resulting wound, if the branch was not too large in diameter.

How to make pruning cuts on larger branches:

-Disinfect your blades before you begin pruning.
-Use a three-cut system for limbs of a substantial weight:
-The first cut is an undercut about a third of the way through the limb and should be placed several inches away from the trunk (or main limb from which the branch is being removed). This cut protects the bark from tearing as the main weight of the limb is removed (with the second cut).
-The second cut is made from the top of the limb just outside the undercut (i.e., slightly farther from the trunk). Once this cut is complete, a stump will be left.
-The third cut is made just outside the slight swelling where the limb joins the trunk (i.e., the branch collar). When left intact, the branch collar will grow over and cover the resulting wound, if the limb was not too large in diameter.

This website shows schematics for both pruning types.


Fire blight:
-Fire blight is a bacterial disease that attacks certain trees and damages the bark, leading to the death of the affected branch (and possibly of the tree).
-It spreads most effectively during the spring and can be spread via contaminated tools.
-Apple trees and mountain ash are both susceptible to fire blight.
-Prune susceptible trees during the winter months so wounds have time to dry before the bacterium is actively spreading.
-When pruning a tree with fire blight, cut off diseased branches, being sure to cut back to healthy wood.
-Disinfect your cutting tools between each cut.

Other notes:
-Prune maples (and box elders) after they have leafed out, to avoid running sap from open wounds.
-Randy included this handout.