If you are trimming heavy tree limbs, then you need to be really careful not to damage the bark or interfere with the tree’s natural healing response. Doing it right is no more challenging than doing it wrong, especially if you think ahead to how much work it would take to remove a dead tree!
Here’s the way to cut large tree limbs into your lawn in three easy steps.
How Trees Heal
The reality is, trees do not really heal like we do. When you cut a tree branch, the tree creates a distinctive callous tissue (such as a scar) that covers over the wound to keep out disease and decay. That scarred part of this tree will be there indefinitely, sealed off so the remainder of the tree can keep growing. It’s extremely important to prune trees properly so that we do not interfere with this process — wrong pruning will leave the tree weak and vulnerable to disease.
In the top photo, you can see the evidence of numerous large pruning cuts. The lumps show well cured pruning scars, many of them completely covered over. The “donut” shaped scar is normal, too. The callous tissue develops from the outside edges toward the middle, so it is still in the process of sealing over.
How to Cut a Tree Limb
Proper pruning of tree limbs entails three cuts:
Cut #1, Notch Cut: Cut a small notch in the base of the limb, 2-3 feet away from the back, and roughly a quarter of the way through. This notch will keep the bark from splitting when you make the next cut.
Cut #2, Relief Cut: Just away from the top notch, make a relief cut completely through the branch. This eliminates the weight of the branch, so you could make your final cut with no branch falling and splitting.
Cut #3, Final Cut: This is the one which matters! Your final cut ought to be right where the branch collar (that swollen bump) adjustments to smooth branch bark. Stick to the slant of the branch collar. If you can not match your saw to the crotch at the ideal angle, then cut it from the ground up.
Common Tree Trimming Mistakes
Cutting the Branch Too Short: We used to think that branches must be cut off flush with the back — boy, were we ever wrong! The branch collar is responsible for forming the scar tissues. If you cut into the branch collar, the tree will have a very difficult time recovering. When you see rotten holes in tree trunks, or seeping wounds, you are taking a look at the aftermath of cutting off the branch collar.
Leaving the Branch Too Long: The branch collar on the truck can only do its job of allowing the wound to heal if each the branch it has to cover over continues to be removed while leaving the branch collar itself intact. From the photograph on the right, you can see how the branch stubs which were left too long are interfering with and really preventing the recovery process from happening.
Struggling to generate the Relief Cuts: If you are not able to produce the relief cuts and eliminate the majority of the weight of the limb prior to trimming back the branch to the trunk, you face the risk of getting the branch split off. This can cause significant damage to the back, as seen in the photograph at right. This can make the wound on the back prone to pest and disease infestation and take much longer to cure.