Can Pruning Kill a Tree?

Many first timers are afraid to prune for fear of doing it incorrectly and hurting the tree. The big question is . . .

Can pruning kill a tree? No, just by following few simple rules anyone can prune trees without hurting them. Now if you were to cut the tree off at the ground you will kill it, but generally, it is hard to kill a tree just by pruning some branches.

You might want to prune a tree for many different reasons. Lets go over some of the basics, so that you don’t stress or worse yet, kill the tree.

How to Trim a Tree Without Killing It

Remove Dead Branches From Trees

I find that when I start on a pruning project it is easiest to start with the dead limbs or sections first of the tree. If a limb is dead just on the end you can remove only the dead part back to a branch or fork.

Don’t leave a stub because most trees will not generate growth from a stub so it will just die back to the next branch anyway. Cut the limb all the way back to another branch even if you are cutting off part of a “live” branch.

If you are cutting dead out of a bigger tree and only part of the limb is dead you might want to remove the whole limb back to the trunk if the part that is left doesn’t get any sunlight to the leaves. Without a strong energy source, most limbs die all the way back to the trunk over time anyway.

Once you remove all the dead, it just seems easier to notice the next step.

Remove Damaged or Broken Limbs

If you notice any limbs with damaged sections or even cracked / broken sections, you will want to cut them off. Once a limb is cracked it will more than likely die or grow for a couple more years until the damaged part gives way to the weight of the limb and then breaks completely.

If it a critical limb to the shape of the tree you can try cabling the limb to relieve the weight as it grows.

Remove Bad or Weak Crotch From Trees

Some trees are more prone to having limbs that have a “weak crotch”. This is when I limb grows in a more upward direction like the trunk instead of outward away from the trunk. This structure tends to create a very weak limb which can easily break later from just the weight of the limb or from a wind storm.

The earlier you can catch a weak crotch structure and remove it in the trees growth the better. These limbs also will try to compete with the leader of the tree. Many times if these limb structures are not caught at an early age you will have to cable the limb to the trunk to keep it from splitting out in a wind or ice storm.

A great example of this is the Bradford Pear. Just when the tree gets a nice size, a windy day will cause a big section of the tree to break off. Then you are just left with the decision as to whether to remove the whole tree or see if you can shape it enough after remove the damaged section. Unfortunately what remains is usually very weak so when you have the next wind storm other sections will break off.

Remove Cross Branches From Trees

Now that you have all the dead and weak crotch limbs removed, look for any limbs that are rubbing on each other or will be in the near future. To decide which of the two to remove look at the growth pattern of the two limbs. You will want to remove the limb that is growing towards the side or through the middle of the tree instead of straight out from the trunk.

In many cases you can just remove parts of a limb if it is growing towards another main limb. Just keep in mind that limbs will just keep getting bigger and longer so ultimately you will want to keep the one that best fills the over shape of the tree and remove the one that isn’t doing that.

Remove Low Branches From Trees

Now step back and observe if there are branches that are just too low. The ones you have to duck under when cutting grass or walking past on sidewalks or maybe they are too low to park your vehicle under.

Usually you will want to remove the whole limb back to the trunk instead of just trimming off the end of the branch. As the tree grows limbs do not get higher. In fact most limbs tend to droop down more as they get longer, so you might as well remove the whole limb if the end of the branch is too low.

Remove Branches That Are Growing Into Structures

If you tree happens to be next to a house or garage or any structure you will need to pay special attention to limbs growing in that direction. When the tree is smaller it is easy enough to prune back limbs that are getting close, but as the tree grows over the structure it can be a completely different challenge.

Smaller limbs can be pruned by cutting them and letting them land on the structure. The larger limbs are a different story. You will want to hire a professional to remove those limbs in a way that will not destroy the structure.

Limbs can be very heavy as they get bigger and longer. Professionals will usually have a bucket tree that they can use to cut the limbs off in many pieces that they can handle as they cut them.

Other professionals will use ropes and tie the limbs so that they can’t fall but a couple of feet when they are cut off and then lower them in a controlled way as to not do any damage to the building.

If your roof is not very steep you could stand on the roof and cut the limb section off that is over the roof then using a ladder at the trunk finish cutting off the rest of the limb. You do have to know how to cut limbs off in a way so the limb doesn’t hit the ladder when it crashes to the ground.

Leave The Branch Collar At The Trunk

When you cut a branch off at the trunk you have to make sure to leave the branch collar. This special part at the base of the limb where it comes off the trunk is the healing part that grows over the cut limb.

If you cut the collar part off because you are cutting the limb off too close to the trunk, you can impair the healing of the cut which will invite insects and diseases to get into the trunk of the tree.

If you look closely at the base of any limb you will notice that the base is bigger than the diameter of the limb. That is the collar. The part where the thickest looks similar to the rest of the branch is where you will make the cut. Once cut the collar is what will grow over the cut.

Pruned Tree Too Much – What To Do

So what if you finish pruning and you just cut too much off? Lucky for you nature has a way of fixing issues. While your tree might look a little ugly for a couple of years it will eventually fill back in.

You will want to pay special attention to the tree over the growing season since the excess pruning will be stressing the tree. If you run into a dry time you will want to water the tree. You will also want to feed the plant with some fertilizer to help it along.

If you cut too much of the canopy off – more than 30%, you might have to put some shade boards on the trunk where it gets the hot summer sun at around 2 pm in the afternoon. This will help protect the trunk from getting sunburnt which can kill the tree.

A shade board can be any kind of temporary board or covering that will allow the tree to adapt to the new level of sunlight. These can be removed after a season (next year).

What is the Best Time of Year To Trim Trees?

For the majority of trees the best time to prune them is late winter to early spring just before the buds start swelling.

There are a couple of exceptions such as maple, birch and walnut trees. You will want to prune them in the mid-summer or mid-winter when they are completely dormant.