Treating Termites in Trees

Each year as we move into storm season here in Brisbane, the trees around our properties can become more of a concern, especially when two of the more vicious local species of termites are involved.

Most trees are an asset; providing shade, cleaning the air, hosting local wildlife. Some generous species provide us with special treats like mangos and macadamia nuts. Trees also supply us with a most remarkable building material: wood. Light and strong, humans have utilised this excellent resource for thousands of years. Timber is also very durable and difficult to bio-degrade. Special niche organisms developed to unlock the nutrients trapped in the wood such as decay fungi, auger beetles and of course termites.

Are all termites very destructive?

No, not all termites are very destructive, so you need to know your enemy and where they live. Some local species of termites damage timber and their host trees relatively slowly. A classic example of this would be Microceretermes spp. The bulky arboreal nest, whilst visually spectacular, only conceals minor damage to the trunk behind. Close examination of the rest of the tree should only reveal shallow, superficial mud tubes (unless another species has been at work). Unless they are proving particularly troublesome or are in close proximity to your house we generally advise leaving them alone (the nest may be used by other wildlife in the future).

So which termites do we need to worry about?

This comes down to our most common suspects, Coptotermes and Schedorhinotermes. Both of these types are a massive threat to your home and are the termites most commonly associated with serious structural damage. They are also capable of nesting in a similar way to each other, and frequently do. You’ll often find them inside living and dead Gumtrees and stumps and their nests are not as obvious as those of Microcerotermes spp. You have to know where to look for these guys and it may involve some bush bashing to find them.

How do termite nests start?

Initially, the king and queen termites (alates) burrow into the base of the tree or in and around the root crown. As the colony grows, more space is required. Now, furnished with worker termites, the queen sends them off to hollow out the trunk of the tree, gaining food as well as more living room. Soon the trunk will be seething with termites, even though it may appear undamaged to the naked eye. In this way large amounts of structurally important timber can be removed, significantly weakening the host tree. Along comes an event like “Oswald” (the ex-cyclone we had in January 2013) or a severe storm (like the one in the Gap a few years ago) and suddenly it all comes crashing down. Badly damaged trees may only require a gusty breeze. Remember that the damage can continue for many years, and just because it didn’t fall last time doesn’t mean that it won’t fall next time.

How do you treat termite infested trees?

Treating infested trees usually involves drilling into the trunk at several angles and identifying the cavity made by the termites. The important nursery (where the queen lives) can be identified by its elevated temperature. Liquid termiticide can then be administered directly into this area. Often the damage to the tree may be extensive and removal of the tree may still necessary for safety reasons.

If you suspect that a tree in your yard is concealing more than you would like, get in touch with a termite specialist and have them take a look. Best to route out these pests before they do too much damage!