Pruning Damaged Trees
Trees are resilient by nature and can generally withstand harsh weather conditions. They survive most winters without too much damage, and any damage sustained can be left to heal naturally without man's interference. Trees have the ability to compartmentalize and seal their wounds by forming woundwood (callus tissue). However, Mother Nature alone cannot repair the extensive damage caused by severe winter storms.
Professional tree experts know all about the biology of trees and won't prune a branch without a motive – there's a good reason for what is cut and how it is cut. Arborists are experts in the tree pruning field, but foresters, forestry technicians, biologists, ecologists, horticulturists, loggers and land-clearing contractors may also be consulted for other tree issues (such as disease and clearing). You should make sure that the professional you hire to do the job is not only experienced but also certified in your province or state, has the proper equipment and has liability insurance to cover injuries suffered while repairing trees on your property. As further precautions, you should verify any references given and obtain more than one written estimate of the work to be carried out.
In any case, if a tree company advertises topping as a service, or uses climbing spikes to prune live trees, please do your trees a favor – call someone else! Topping, as well as the use of spikes on a live tree, is harmful to trees.
Tools
If you want to do your own pruning, consider your tool inventory. Wounded trees will further benefit when the right pruning tool is used for a particular pruning task. Trying to cut a branch that is larger than the recommended maximum size for any particular tool not only damages the tool, but can also cause torn and disease-prone plant tissues.
Whatever tools you choose to use, ensure that they are sharp and clean before starting any pruning exercise. Dull tools may cause more damage in the long run. Properly sanitized tools prevent the spread of disease, although there is less chance of spreading disease when pruning during the dormant season. Pruning tools can be sterilized in a solution of 1 part bleach to 10 parts water, then thoroughly dried.
Some basic pruning tools include:
- Pruners. Use them on branches up to 1/4" thick about the thickness of a pencil.
- Loppers. Use these on branches up to 2" thick. Capacity depends on the size and design.
- Pruning Saw. Any saw will cut branches with diameters equal to or less than 1/2 the length of the saw blade.
- Pocket Knife. Used for cleaning and shaping the wounds.
- Pole Pruners. These are pruners on a 6' to 18' pole, allowing you to cut branches up to 1-1/4" thick (some may come with a pruning saw) while standing safely on the ground.
- High-Limb Chain Saw. This non-powered saw is used to saw high branches while you remain standing on the ground.
- Chain Saw. Handy for cutting large branches into manageable pieces.
- Safety equipment. Chain-saw chaps, hearing protectors, eye protection and gloves are the most basic when working with chain saws.
- Hard Hat.
Dealing with Major Damage
Although total tree removal is recommended in several cases, it is a task that can wait for warmer weather, when it will be easier to assess a tree's overall health. The removal of a tree may be a consideration under the following circumstances:
- When the entire top is broken off (see photo above)
- When the weight of the ice has caused the trunk to split most of its length
- When one of the arms of a Y junction on the trunk has started to split away and is beyond saving (see photo at right).
Minor Crotch Damage
In theory, Y junctions should never be allowed to develop when trees are young; however, in practice, many trees are left to develop branches with narrow angles of attachment and tight crotches. Such junctions are weak, lead to the development of included bark and make trees vulnerable to damage. However, when one side of a Y junction breaks, it is often possible to save the other side and make it become a dominant central leader. Where the Y junction split is small, a 45° diagonal pruning cut (see Figure 1) may be made to remove the weakened limb.
To strengthen a weakened joint, a cable can be joined from A to B. Branch on the right should be removed at points C down to D if junction at E is starting to split.
