Termites are insects known for their ability to digest cellulose, the primary material in wood and plant fibers. While most species prefer foraging on dead, decaying wood like fallen logs and stumps, the answer to whether they eat live trees is definitively yes, for certain types. A few aggressive species actively attack and consume the wood fibers within a living tree. This article explores which species pose a threat to live trees and the specific ways they cause damage.
The Termite Species That Target Living Wood
The most destructive species known for attacking healthy, living trees is the Formosan subterranean termite. This insect is sometimes called the “super termite” because of its large colony size and rapid rate of wood consumption. They are common in warmer, humid regions of the United States, particularly the Gulf Coast states, where they infest trees like live oak, ash, and cypress.
Other types, such as Dampwood termites, are also found in live trees, but they typically target sections that are already decaying or water-damaged. They thrive in high-moisture environments, often colonizing the heartwood of mature trees where water has accumulated due to injury. These species are capable of establishing nests and causing significant structural damage within the main trunk of a living specimen.
How Termites Bypass Tree Defenses
A tree’s primary defense against pests is its bark and the toxic chemicals contained in its sap and heartwood. Termites rarely attack sound wood, instead exploiting existing weaknesses to gain entry. They target trees that are stressed, unhealthy, or have suffered physical trauma.
Entry points are often created by improper pruning cuts, storm damage that exposes the inner wood, or wounds caused by lawnmowers scraping the base of the trunk. Once the protective bark layer is breached, termites access the softer wood beneath. Fungal decay also plays a role by softening the wood and predigesting the cellulose, making it easier for the insects to consume.
Formosan termites are unique because they can establish carton nests above ground within the tree trunk, even in seemingly healthy deciduous trees. They construct these protective nests using a mixture of soil, wood fragments, and saliva. This allows them to bypass the need to forage entirely from the soil. By eating the wood from the inside out, they hollow the trunk, compromising the tree’s structural integrity long before external signs become obvious.
Identifying Termite Damage in Live Trees
Homeowners should look for several signs of an active termite infestation in a live tree.
Signs of Infestation
- The presence of mud tubes running up the trunk or along exposed roots. These pencil-width tunnels are constructed from soil and wood particles, providing a protected pathway for subterranean termites to travel between the soil and the wood.
- The appearance of frass, which are small, granular droppings that resemble sawdust, often accumulating near the base of the tree.
- A hollow sound when tapping the trunk, which suggests the termites have created extensive galleries inside the heartwood. This internal damage significantly weakens the tree, making it susceptible to falling in a storm.
- The appearance of swarming alates, or winged reproductive termites. These insects emerge from the tree to mate and establish new colonies, often leaving behind discarded wings near the trunk.
A general decline in tree health, such as wilting or discolored foliage, can also signal that the tree’s internal nutrient transport system has been damaged.
Protecting Trees from Infestation
The best way to protect trees is by focusing on prevention and maintaining optimal tree health. Trees that are well-watered, properly fertilized, and free from stress are less likely to be targeted by termites. Homeowners should avoid causing physical damage to the trunk, such as wounds from lawnmowers or string trimmers, and ensure that any necessary pruning is performed correctly. It is also important to eliminate potential attractants near the tree, such as removing old stumps, dead wood, and fallen branches from the immediate area.
Treatment Options
If an infestation is suspected, professional intervention is recommended, often involving targeted chemical treatments. This can include applying liquid termiticides to the soil around the base to create a protective barrier. Another option is installing termite bait stations that eliminate the entire colony. For severe infestations, a professional may inject a termiticide directly into the tree’s internal galleries to stop the damage at its source.