Carpenter ants and trees

Carpenter Ants and Trees
Carpenter ants are common in log houses and other wooden structures. These insects are primarily a nuisance, and are not likely to cause serious damage quickly. Carpenter ants in tree cavities outside the home can cause acute, long term damage, and may render a tree structurally unsound if the ants' activities go unchecked. Ant workers, 1/4 to 1/2 inch long and reddish brown to black in color, do not eat wood. However, they do excavate shallow nests in moist, decaying wood, creating smooth (as, if sanded) walls. Carpenter ants will generally infest any tree cavity, as long as moisture content is high and the nest is protected from predators. Nests that exist for a number of years may grow to upwards of 1,000 residents and create large hollows inside of trees. The ants' excavation of dead and diseased tissue creates tunnels that
destroy the tree's defensive barriers and expose it to further colonization by fungi and disease. Many trees in forested areas have ant infestations that are evidenced by irregular structures at the base of the tree. Red Oaks, Water and Willow oaks and Poplars seem to be favorites, though no species is immune. Infested tree cavities need not be open at the ground, but can be invaded from below ground or high in the tree canopy.
WHAT TO DO? Inspect your trees regularly, looking for cavities or cracks in the trunk and major branches through which ants could enter. Also look at the base of your trees for abnormal growth forms on the trunk. Carpenter ants climbing on the trunk aren't always a sign of a tree with an infested cavity, but can be an indication of a colony nearby. Look for brown sawdust near the base of the tree, in between the flares of the roots or grooves of the bark. Once a cavity is discovered, it's a good idea to determine its size to assess whether the tree is still structurally sound. Removal of any loose wood inside the cavity will aid in the determination, but never place a bare hand inside the cavity. While carpenter ants can inflict a minor bite, other cavity-dwelling insects and spiders can be dangerous. If the cavity is judged structurally sound, apply a pesticide currently recommended by the UGA Extension Service.
Image source: Bugwood Network
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