Termites in Trees: How to Spot Them and What to Do in Puerto Rico

Termites are a fact of life in Puerto Rico. Our warm, humid climate is close to ideal for them year-round, and they do not limit themselves to the wood in your house. Living and dead trees are on the menu too, and a termite colony working inside a trunk you walk past every day can turn a healthy-looking tree into a falling hazard without much warning from the outside.

The good news is that termites in a tree do not automatically mean the tree is doomed, and they rarely mean the tree needs to come down that week. What matters is knowing what you are looking at, how far it has gone, and whether the structure of the tree is still sound. Here is how to read the situation like an arborist would.

First, know which termite you are dealing with

Puerto Rico has both of the types that matter for trees, and they behave very differently.

Subterranean termites live in the soil and travel up into wood through mud tubes. These are the ones you are most likely to find in a tree, especially in dead sections, old wounds, or the base near the root flare. They need moisture and contact with the ground, so they tend to attack from the bottom up. The Formosan subterranean termite, an aggressive introduced species established on the island, builds large colonies and can hollow out structural wood faster than native species.

Drywood termites do not need soil contact. They live entirely inside the wood and are common in dead branches, fence posts, and untreated lumber. In living trees they are less of a structural threat than subterranean termites, but they are a sign that dead wood is present and being consumed.

Telling them apart in the field usually comes down to the evidence they leave behind, which we will get to next.

The signs of termites in a tree

Termites work out of sight, so you are usually spotting the symptoms rather than the insects. Walk the tree and look for:

• Mud tubes. Pencil-width to finger-width tunnels of dried mud running up the trunk, over the bark, or between the soil and a wound. This is the single clearest sign of subterranean termites. Break one open; if it is repaired within a day or two, the colony is active.
• Frass (drywood termite droppings). Small piles of what looks like fine sawdust or coffee grounds, often in tiny six-sided pellets, collecting at the base of a branch or in bark crevices. This points to drywood termites inside the wood above.
• Hollow sound. Tap the trunk and larger limbs with a mallet or the back of an axe. Solid wood gives a dull thud; heavily eaten wood sounds hollow or papery. This is one of the most useful field tests for how far damage has spread.
• Soft, crumbling wood. Push a screwdriver into suspect areas, especially around old cuts, storm wounds, and the root flare. Wood that gives way easily or crumbles has lost strength.
• Swarmers or discarded wings. After rain, especially in the wet season, winged termites emerge to start new colonies. A pile of small identical wings near the base of a tree means a colony is mature and reproducing nearby.

Why termites matter more than most homeowners think

A termite colony rarely kills a tree outright. Trees are largely made of dead structural wood at the core (the heartwood) surrounded by a thin living layer, and termites feast on the dead part. A tree can keep leafing out and looking green while termites quietly eat away its structural core.

That is exactly the problem. The green canopy tells you nothing about what is happening inside the trunk. By the time the outside shows obvious signs, the wood that holds the tree up in a windstorm may already be compromised. In a place that sees hurricane-force winds on a regular basis, a hollowed trunk is not a cosmetic issue, it is a failure waiting for the next storm.

Termites also tend to move in where the tree is already weak. They are drawn to dead wood, old wounds, poor pruning cuts, and roots damaged by construction or flooding. Finding them is often a signal that the tree has an underlying problem worth a closer look.

Which trees are most at risk in Puerto Rico

Any tree with dead wood or ground contact can host termites, but a few common island species come up again and again:

• Mango trees, especially older ones with deadwood and past storm damage, are frequent hosts.
• Mahogany and other dense hardwoods can be attacked once decay gives termites an entry point.
• African tulip and other fast-growing softer-wooded species decay quickly and invite infestation.
• Flamboyán, with its wide, heavy limbs, is worth watching because termite-weakened branches over a driveway or roof are a real hazard.

Palms are different. Royal and coconut palms are not true wood and are generally not primary termite targets, though termites will consume a dead palm trunk or an old cut frond base.

Can the tree be saved, or does it need to come down?

This is the question that actually matters, and it comes down to structure, not the presence of insects.

The tree can often be saved when:

• The termites are confined to a dead branch or an isolated dead section that can be pruned out.
• Tapping and probing show the main trunk and major limbs are still solid.
• The infestation is caught early and the underlying moisture or wound problem can be corrected.

In these cases, the right move is usually to remove the affected wood, address whatever is feeding the colony (a broken limb, standing water at the base, soil piled against the trunk), and monitor the tree. Termite treatment of the surrounding soil may be recommended, but that is a job for a licensed pest control operator, not a tree crew, and it works alongside the tree work rather than replacing it.

The tree usually needs to come down when:

• Tapping reveals extensive hollowing in the main trunk.
• A screwdriver or probe sinks into the trunk wood at multiple points.
• The infestation is combined with a significant lean, large cavities, or fungal conks, which together signal advanced decay.
• The tree is within striking distance of a house, driveway, power line, or anywhere people gather.

A structurally compromised tree near a target is a hazardous tree removal, and after a storm it can become an emergency. The point of catching it early is to schedule the removal on a calm day rather than dealing with it at 2 a.m. with the tree already on the roof.

What you should not do

Do not spray over-the-counter insecticide on a tree trunk and assume the problem is solved. It will not reach the colony, and it can leave you with a false sense of security about a tree that is still weakening inside. Do not ignore mud tubes because the canopy looks healthy. And do not attempt to fell a termite-hollowed tree yourself. Compromised wood behaves unpredictably when cut. A trunk that looks solid can splinter and fail in a direction no one expected, which is exactly how DIY tree jobs turn into injuries.

How we handle it

When we come out for a tree you suspect has termites, our first job is to assess structure. We sound the trunk and major limbs, probe suspect areas, examine the root flare and any cavities, and give you a straight read on whether you are looking at a pruning job, a monitoring situation, or a removal. If the tree can be saved, we tell you so and remove only what needs to go. If it is a hazard, we explain why and quote the safe way to take it down, including cleanup and the stump.

We also tell you honestly when the real fix is soil termite treatment from a pest control professional, because we would rather point you to the right trade than sell you tree work that does not solve your problem.

If you have found mud tubes, sawdust piles, or a hollow-sounding trunk on a tree near your home, do not wait for the next storm to make the decision for you. Call us at (787) 513-9441 or request an orientation. We serve all of Puerto Rico, our crews are licensed and insured, and for storm emergencies we dispatch 24/7.