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Trees in the built environment require some maintenance in order to get along
with other elements on the site.
Typically, pruning is thought of as simply keeping a plant in it's place or
just making it smaller.
In reality, pruning is necessary to improve clearance, reduce risk,
improve ascetics and good plant health care.
Plant selection plays a role in pruning.
Be sure when you're planting a new tree, you select a tree with a good,
strong central leader system.
And not one that has a co-dominant stem.
This is an example of a co-dominant stem.
You can see the wide angles here, and there's no real central leader system.
As the tree grows, this will have the risk of splitting.
Which can be a potential risk or hazard later on.
The equipment for pruning's fairly simple.
The majority of the work can be completed with three simple tools.
First, we have the bypass pruners, which is for
branch sizes of less than a quarter-inch.
Then next we have the bypass loppers, and
this is typically from a quarter-inch up to three quarter-inch.
For anything larger than one inch in diameter, you wanna use a pruning saw.
This has a specialized tri-cut blade which was made especially for pruning branches.
Pruning is considered one of the best-worst maintenance practices performed
on trees.
The reason is that pruning is actually wounding the tree in order to accomplish
our objectives.
Wounds can lead to disease and decay if they're not pruned properly.
Also, excessive pruning, or poorly timed pruning, can lead to stress, decline,
and even death.
Never top a tree, this is a sure way to weaken the tree structurally.
Topping is actually excessive pruning between branch growing points,
leaving stubs and wounds, which lead to decay and die-back.
There should be a purpose for every cut that you make on a tree,
based on the objectives for pruning.
The primary objective of pruning should be to develop a strong structure.
Structural pruning of younger trees can be a holistic approach
to training young plants to grow into stronger, safer and healthier trees.
Some of the objectives of pruning include removing non-beneficial plant parts,
such as basal sprouting.
Other non-beneficial plant parts include epicormic sprouting,
which are those vertical branches growing up in the tree.
And finally other non-beneficial plant parts include crossing branches, or
branches with poor branch angles.
Proper technique in pruning is essential for wound recovery.
And in order to make a proper cut,
some branch components are gonna be necessary for us to ID.
First we need to identify branch bark ridge, which is this raised area of
compressed bark, between the main stem and the branch.
The other part that was important to identify is the branch collar,
which is typically located on the underside of the branch,
typically close to the branch union.
And together,
these two will help us determine where we need to make our final pruning cut.
No cut should ever be made inside this line.
Inside this is called the branch protection zone, which
contains specialized healing properties to help that wound seal properly.
We're going to remove this smaller branch back to the primary stem or trunk.
It's called the Ternary Method which is actually three cuts.
First we're going to make a pre-cut which is typically on the underside of
the branch.
And we're going to go in about one-third the diameter of the branch.
And the purpose of this is to prevent
the branch from tearing once we start making our second cut.
This is our top cut, and we'll go about two inches or so
past where our undercut is for the pre-cut.
And then we start cutting.
And as we cut, we're gonna see the branch start to fall.
And as it falls it's gonna stop right where that pre-cut is.
So, we can finish up.
Now, that's two cuts.
Remember, there's three parts to this.
If we leave this, this is a stub which cannot support any types of leaves or
branches to keep it alive.
So all this will be is a conduit for decay.
So what we're gonna do is go outside the branch bark ridge and the branch collar,
which we found earlier, and make our final cut.
So we've got the smallest wound possible so it can heal quickly and effectively.
To seal off against any type of fungal organism which can cause decay.
Once the cut is made, leave it to the tree to seal the wound and recover.
Do not apply any wound dressings.
Take into consideration timing of pruning.
Never prune a tree which is drought stressed, and
never remove excessive amounts of green tissue at any one time.
Pruning can be done about any time the wood is not frozen.
However, there are better times to perform this activity.
This is during the growing season when the tree can seal the wound fastest,
reducing decay.
In any type of tree care operations, never let the situation exceed your skills.
Pruning on larger trees can be dangerous for you and the tree.
Call an ISA certified arborist for help with your tree care needs.
For more details on proper pruning, go to the education store and
download the publication, Tree Pruning Essentials.
Take care of your trees and they will take care of you.
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