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What to Do About Carpenter Ants in Trees

Carpenter ants are a common pest that can be found in trees across the United States. 

The carpenter ant is a type of ant that has been known to forage on dead trees. They will also nest in already unhealthy, dying, rotting, or weakened trees. 

Carpenter ants have been found infesting healthy live trees as well at times. 

Signs of carpenter ants include piles of sawdust near the entrance hole or holes to their nests and rapid deterioration of the infested tree, which may eventually lead to its death from decay if left untreated.

In this article, you can read more about how carpenter ants infest trees, and what you can do about it.

What Are the Signs of Carpenter Ants in Trees?

Carpenter ants are very active insects that at times infest trees, usually ones that are already dying or weak though.

alone carpenter ant crawling on the woods

Therefore carpenter ant nests in a tree often go unnoticed until the carpenter ant population is quite large and their damage to the tree becomes very noticeable. 

It’s not unheard-of for carpenter ants to weaken the tree to the point that it topples over.

Here are two signs to look out for, if you want to find carpenter ants in trees:

  • Sawdust at the base of the tree
  • Rapid deterioration of the trees


Carpenter ants have a very distinct tell: they create piles of sawdust when they’re digging out tunnels, which will gather at the base of the tree.

Ants don’t actually eat wood – this is a myth. Instead, they dumb out the chewed-up wood outside of their nest, where it won’t bother them any longer.


Their nests are made up of tunnels, which obviously take up space in the tree. As they chew through the wood, they need to dumb the sawdust somewhere. 

If you see a tree, especially if it looks unhealthy, with piles of sawdust around it, there’s a good chance it’s been invaded by carpenter ants.

Rapid Deterioration

Rapid deterioration of carpenter ants in trees is hard to detect because carpenter ants nest inside already weak, dying, and rotting trees. 

The presence of carpenter ants may not be visible on the outside at first, but as the colony grows bigger, the ants dig out more space. This leads to the tree dying faster.

If you see a tree that is deteriorating faster than it should, you might have an ant problem on your hands.

infested wood

How to Get Rid of Carpenter Ants in a Tree

The method of getting rid of carpenter ants in trees is very much like getting rid of them in your home or other places.

  1. You need to figure out where they entered
  2. Use insecticides to kill them off
  3. Inspect the health of the tree
  4. Yearly treatment

Also read: How to get rid of carpenter ants

Locate Entrance Points

Carpenter ants are called carpenters because they like to nest in wood [1]. When carpenter ants move into a tree, it’s usually near or in an area where there is already some rot or other damage. 

The first step to getting rid of carpenter ants in trees is locating their entrance points. 

This will give you a starting point.

Try following the ants for a while. They usually lead you directly to the entrances of their home.

carpenter ants on tree branch

Use Insecticide: Dust, Liquid, or Bait Strips

There are a lot of carpenter ant control methods out there. The best method for carpenters ants in trees is to use insecticide. You can either use powder, liquid spray, or bait traps. 

The best solution is usually a mix of them all.

  1. Take the ant killer dust powder and dust around the base of the tree.
  2. Place a few ant bait stations around the base as well.
  3. Spray some insecticide directly into the entrance points – this will both kill some off as well as drive them out. As they run down the tree, they will encounter the powder and bait stations.
spray bottle to kill ants

Inspect the Health of the Tree

It is important to know that carpenter ants nest in already unhealthy, dying rotting, weakened trees. 

If a tree appears healthy and strong with no evidence of decay or damage then there is likely not a carpenter ant infestation.

Now, after you’ve driven out the carpenter ant colony, it’s time to look at the tree. If it’s beyond repair, there’s no reason to keep fighting to keep it alive.

rotten tree

Yearly Retreatment

If the tree you’ve saved from the ants is healthy enough to recover, you might need to do a yearly treatment against ants.

It’s likely that the ants come back – after all, you just drove them out of their home. Check back every once in a while for signs of ants.

Why Do Carpenter Ants Infest Trees

Carpenter ants infest trees because they’re easy to dig through if the wood is rotten or damaged. It provides them with shelter, and they’re great at digging through the wood.

The Tree Is Rotting Which Makes It Easy to Dig Through

If a tree is rotting or decaying, due to the presence of fungi, the wood is much more malleable. This means it’s easier for carpenter ants to dig through it. It provides them with a good shelter, which is why this species of ants like to nest in trees.

rotten tree infested by ants

Carpenter Ants Infest Already Weakened Trees

Carpenter ants nest in trees that are already unhealthy, dying, or rotting. If carpenter ants have infested a tree, it is because the tree was weakened from disease and decay before they moved in. 

You will rarely see carpenter ants nesting in completely healthy trees, as the wood will be too hard for them to dig through quickly.

What Trees Do Carpenter Ants Infest?

Carpenter ants are, despite their small size, very smart when it comes to choosing where to nest. They won’t nest in any tree, but rather a rotting tree (as discussed).

Here are some places where you can find carpenter ant nests.

Rotting Tree Stumps

Carpenter ants will infest rotting tree stumps. When they nest here, they can connect the tree stump to tunnels in the ground, making a hybrid nest – part tree part ground.

Tree stumps rot easily, which makes them perfect targets for carpenter ants looking for a place to nest.

Tree Stump

Injured or Dying Trees

Carpenter ants will, as said, nest in any already injured or dying tree. 

The best preventative method to keep carpenter ants away is to keep healthy trees growing strong. If you know carpenter ants are present in your trees, you should take action immediately.

Damp Wooden Structures

Carpenter ants won’t just infest trees, but also other wooden structures. An example of this is wooden beams.

The same rules apply: if the wooden structure is weakened, carpenter ants might move in. This can be due to too much exposure to moisture.

Do Carpenter Ants Harm Trees?

Yes, carpenter ants do harm trees. While they don’t eat the tree, they will burrow through it, creating tunnels for their colony. This will harm the tree by increasing the rate of deterioration.

queen ant laying eggs together with ant workers

Carpenter ant nests in trees are a result of already unhealthy and dying rotting trees [2], but even though the tree is already dying, carpenter ants aren’t helping it.

This is one reason why you should try to get rid of carpenter ants as soon as possible. Carpenter ants in trees will damage it, and can eventually kill the tree.

Will Carpenter Ants Kill My Tree?

Yes, eventually carpenter ants will kill a tree. They don’t do so intentionally, as they’re simply looking for a place to live – but if the colony and nest become too big, the tree won’t be able to survive the excavating. The bigger the colony, the bigger the chance of the tree dying.

Should You Cut Down a Tree With Carpenter Ants?

Not necessarily. Before cutting down a tree because of a carpenter ant infestation, you should inspect it. It might not have taken enough damage to be fatal yet. Sometimes a tree can recover from a carpenter ant infestation.

ants foraging

Do Carpenter Ants Nest in Trees?

Yes, carpenter ants will build their nests and live inside already weakened or decaying tree limbs. They can be found nesting in any kind of deadwood such as stumps, logs, dead branches, etc.


Carpenter ants will nest in trees, but only if they’re already unhealthy. This can be due to rotting. These infestations can eventually lead to the death of a tree, but if you act fast enough, you might just be able to save it.

Carpenter ants will infest both trees, stumps, and other wooden structures. As long as they can chew through the wood, it’s good enough for the carpenter ant.

About Teodoro Pittman

Teodoro is a nature and animal lover. He specifically focuses on insects, such as ants, bees, and the like. In his free time, he takes care of his own ant farm, where he analyzes their behavior. Teodoro has spent the last 7 years studying the intricate behavior of these small creatures.

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