Termites seek cellulose, the organic fiber that forms the structural component of wood. While they prefer dead or decaying material, an infestation in a live tree often signals an underlying health issue or injury that has exposed the softer inner wood. Early detection is important because these insects can rapidly compromise the tree’s structural integrity, posing a safety risk. They may also spread to nearby wooden structures like your home. Recognizing the initial signs of activity is the first step in mitigating potential damage.
External Indicators on the Trunk
The most common sign of subterranean termites is the presence of mud tubes, which are pencil-sized tunnels built from soil, wood particles, and saliva. These earthen structures serve as protected highways, allowing termites to travel between their underground colony and the wood source while shielding them from predators and dry air. They are typically found traveling up the trunk or along exposed roots, often blending with the bark’s color.
Drywood termites do not maintain contact with the soil and leave behind a different indicator: frass. This frass is their fecal matter, expelled through small openings called kick-out holes. Unlike sawdust, termite frass appears as tiny, hard, six-sided pellets that collect in small piles near the entry or exit points.
Visible boreholes may also appear on the trunk where the bark is damaged or missing. These small openings can be points of entry or the kick-out holes used by drywood termites to push out waste. Subterranean termites rarely leave visible droppings outside the wood, instead incorporating their feces into the construction of their mud tubes and nests.
Evidence at the Tree Base and Soil Line
The appearance of discarded wings is a significant sign of a mature termite colony. Reproductive termites, called alates, shed these wings after a swarming event. The wings are typically uniform in size and found in small, scattered piles near the base of the tree or on nearby surfaces. Finding these wings indicates a large, established colony is nearby.
Live swarmers (winged termites) can sometimes be observed emerging from the ground or the base of the tree, usually triggered by warm temperatures and rainfall. Subterranean termites often swarm during the spring, while drywood termites may swarm during late summer or fall. Their emergence is a direct warning sign that they are attempting to establish a new colony.
Subterranean termites require access to the soil to maintain moisture levels and often exploit entry points at the base of the tree. Inspecting the root flare (where the trunk widens at the ground) may reveal small tunnels or damaged areas where termites access the wood. Digging lightly around the base may even reveal worker termites or small egg clusters in soft, moist soil, indicating a subterranean nest.
Assessing Internal Damage
Internal damage can be assessed even when external signs are minimal, which is crucial for determining the tree’s health and safety. The tapping test involves gently tapping the trunk with a rubber mallet or tool handle. A healthy, solid tree produces a dull, low sound, but a hollowed area produces a distinct, high-pitched sound, signaling the presence of internal galleries.
Probing requires a small, blunt tool to gently test suspicious areas of the bark or wood. If the tool pushes into the wood with little resistance, it suggests underlying tunnels or wood that has become soft and compromised. Use this technique with caution to avoid unnecessary damage to the living parts of the tree.
Faint sounds of termite activity can sometimes be heard near heavily infested areas, described as a soft rustling or clicking sound. These sounds are made by worker termites chewing through the wood or by soldier termites communicating a warning. While difficult to hear without specialized equipment, a quiet listener may detect this activity on a calm day.
Visual signs of advanced structural weakness are the most serious indicators of extensive damage. These include large vertical cracks in the trunk, areas where the bark is peeling away to reveal tunneling beneath, or excessive dieback of large limbs. If a tree exhibits significant hollowness or decay, its weight-bearing capacity is severely reduced, increasing the risk of the tree or its branches falling.
Next Steps After Identification
Upon confirming termites, contact a certified arborist or a pest control professional specializing in trees. Treatment in a living tree is complex and requires professional assessment to identify the species and determine the best course of action. Do-it-yourself chemical treatments are often ineffective and may harm the tree or surrounding environment.
Assess the safety of the tree, especially if internal damage is suspected or if the tree is located near a structure or pedestrian area. A professional can evaluate the structural compromise and advise on whether the tree can be saved or safely removed. Avoid disturbing the area, including breaking apart mud tubes or removing frass, as this may cause the termites to scatter and move deeper into the tree or toward other structures.