Pruning or (Trimming)
Proper technique
It is valuable to keep in mind that trimming not only enhances a tree’s appearance, it also helps maintain the health and well-being of a tree. As much as 75% of tree problems could have been eliminated had a tree received proper care initially. As much as 75% of tree problems were caused by improper tree work. Much of the work done to repair a major tree problem could have been handled at a fraction of the cost a decade ago. Problems need to be dealt with when they arise, however the best way to save money in tree maintenance is by preventative care
There are various techniques used in pruning trees. Some are correct, many are wrong and cause future problems. We want to show you the difference. The following are some of the common terms used, right and wrong. [top]
Crown reduction
Crown reduction often includes reducing the height of the tree. If this service is requested, you will want to first clarify why the tree might need to be reduced. Is it because of building interference? Have there been many large branches breaking off the top of the tree in high winds? Is there a safety concern primarily due to the size of the tree?
In some cases the trees may need crown reduction because they have grown to extend beyond the space available. All too often the wrong species is planted in a limited area. Perhaps the tree has grown into overhead wires, buildings or into other trees.
Much of the time however, we are dealing with large, mature trees . The problem then is to make these trees safer for the tenants of the property while maintaining the natural form and soundness of the tree. It is a common belief that a large tree is a dangerous tree. This is not necessarily true. Properly maintained, the large spreading trees add a great deal of value to a property, and become a focal point of interest and beauty. [top]
Topping
Although it is still widely used, the practice of "topping" is on its way out as an accepted form of height reduction for a tree. This type of improper pruning produces instant results for the customer. It may seem that this shortened tree is now safer and will be so for a long time before it needs any work. [top]
The truth
When a tree is topped, the resulting growth forms from what are called "epicormic buds,"or water sprouts. The branches that form from these buds are weakly attached to the main wood of the tree and they grow at a very fast rate. When the high winds and rain of winter come, the "topped" trees often lose their branches before the larger, but properly pruned trees do. These top cuts decay and can be covered over by the growth of the new cambium tissue. The problem becomes hidden internally. Decay spreads inside this tree until these side branches get heavy enough to cause the tree to self-destruct.
Eucalyptus, Ash and Elm are but a few of the trees that we are asked to trim on older complexes where topping has been the norm for many years. Now the trees have no natural canopy shape left, and there is little or no strong branch structure left.
Once again, "topping" refers to a fast, non-selective type of pruning that will be bid at a much lower price but the end results are destructive and costly. [top]
Drop crotching
"Drop crotching" is the textbook term and most correct 
method
of height reduction. Branches are cut to a lower lateral that
is at least one half of the diameter of the cut being made.
[Illustration - drop crotch cuts]
Drop crotch trimming is a method where the over all height of the tree can be brought down without hard topping cuts.
Sucker growth produced by such cuts is not as vigorous as that which is produced by topping, and the overall natural balance of the tree is more easily maintained.
Thinning
Thinning a tree refers to the selective removal of branches for several purposes:
• Increase air movement through the canopy
• Improve branch distribution
• Remove excess weight in the canopy
• Allow for more penetration of light within the canopy
Many times, thinning a tree is a viable alternative to reducing its size. It is important to understand that thinning does not mean to be opened up excessively, This not only stresses the tree, but it also encourages sun damage on the bark. The presence of suckers along the main branches or trunk portions of a tree can be the result of over-thinning.
An incorrect practice known as "Lion-tailing" occurs when all of the inside foliage of a branch has been removed and the remaining foliage now lies only at the ends of the branch. This is obviously a practice that is undesirable because it creates too much end weight on a limb and predisposes it to breaking. Why is it done? Primarily because a climber does not have to climb out to the ends of the limbs to have the tree appear to be done. Proper trimming requires both more time and skill (and sometimes nerves in the newer climbers)!. A skilled and knowledgeable climber will not "Lion-tail" his tree.
Structure Trim
This is a term that is often used by companies and is generally means to open up the structure of the limbs in a way that eliminates or minimises cross over limbs and crowding limbs. When a tree is structure trimmed or pruned, it does not usually involve outside shaping or crown reduction. This is one of the terms that can confuse a client. [top]
Deadwood
To "deadwood" a tree refers to the process of removing dead and broken branches. The phrase "major deadwood " often indicates that only the major or larger, dead branches are to be removed. This might be done in a case where removal of all of the smaller dead wood would be not be cost effective due to the considerable amount of time required. [top]
Cleaning the canopy
"Cleaning out the canopy" refers to the removal of crossing limbs, as well as the dead, broken or diseased limbs within the canopy of the tree. It does not refer to the removal of two-thirds of the tree’s existing foliage!
Thinning cuts may be made to complete the process. Some trees may not require a great deal of work in the canopy so do not always expect a large visual difference once the tree has been cleaned out.
Shaping
Shaping refers to working on the outside of the tree. It can be minor or major and the extent of this term needs clarification so the client understands what to expect. [top]
Raising the crown
Raising the crown or "skirt raising"
There are many reasons why a tree needs to have its canopy raised up:
• Truck clearance, to avoid branches being constantly hit.
• Clearance for pedestrian traffic.
• Clearance off buildings and roofs.
• Street of business sign clearance.
Branches do not always have to be cut back to the trunk of the tree when the perimeter is raised. By reducing end weight on selected branches, the lower branches will rise.
It is somewhat of a common practice to remove a whole limb that is low. This can lead to a tree having a vase-like appearance with too much top weight in the upper part of the canopy.
If a young tree has a lateral or side branch that looks as it will become a problem in the future, it should be removed before it gets too large. Making very large cuts as seen on some trees is not a good practice and should be avoided if possible. The larger the pruning cut, the larger the surface area the tree has to try to close over on a wound. [top]
Proper cut
This is not a pruning term but needs to be understood in this section.
It is very important to understand the difference between a proper cut and one that will cause long term decay in your trees. If a limb or branch is cut flush with the trunk, the natural barriers for fighting decay are compromised. It is often the case where a tree which was trimmed with flush cuts ten years ago, now is hollow or decayed beyond saving. This could have been avoided at the time of trimming had the climbers been aware of how to make a proper cut. Extensive studies have been made over the years on how to make a proper cut but many climbers either do not know this or do not care. The life expectancy of the trees, and value of your property will be affected very poorly, if you do not prevent this from happening. [top]
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