Arboreal - Tree Nesting Termites in Brisbane

Eric Frei

You may have noticed large mud nests in trees as shown adjacent.

Sometimes when the termites have moved on birds peck out the interior and a small entrance hole for a nesting box.

The common termites which build arboreal nests are called Nasutitermes walkeri and Microcerotermes sp.



These termites have mud tunnels to connect to the ground near the base of the tree. They also have a labyrinth of tunnels underground.

What’s interesting to note is that these termites seldom do any damage to either the tree or houses.

I have, under instruction of customers who were told to remove trees because of this, dissected many nests and never found the tree eaten away. The termites seem to do a little chewing around the bark but for the most part the trees are fine other than a few mud tunnels.

Now it’s wise to ID these termites to make sure. Look for the mud tunnel, it will be there, and what I do is scrape it open to find the termites. I’ve attached a picture so you can see two termites and the exposed tunnel.The termites are quite large, maybe 7mm long, and have a distinct dark head in most cases … I do find the odd one that’s a bit different but there’s males, workers etc.

Their head is slightly pointed, like they have a beak or something, these are Nasutitermes.



Now if you are concerned the tree may have been eaten or the strength of the tree above the nest weakened then you can tap the trunk near the nest to see if it sounds hollow. There are other ways to and one is drilling with a small drill. If you are concerned about getting rid of them then I’d suggest getting a pest controller in and having them treated so the whole colony dies. But do not destroy the nest till that’s done, you need the colony functional for poisons and baits to work correctly.

__________________

Eric Frei

The termites in the following pictures are the Microcerotermes sp.

What I done here was cut the nest and log up. Note that the wound and decay was already present in the tree, note that little to no damage is being done by the termites.

In this pic I sliced the bloodwood's surface with the chainsaw to illustrate the wood was not eaten and you can see fresh kino.



Here I cut it along the other axis, you can see the wound decay and termite activity.



And of course a close up of the termites.

Attached Thumbnails

     

__________________

Bernard Keays

Ekka,

Where did you learn about termites? I have been to one workshop presented by amalgamated pest control but it was mostly about breaches into houses and how they get in. There was bit about their biology, vigilance and treatment methods. It was interesting but it was basically pitched at leave it to us we're the experts...

__________________
Bernie

Eric Frei

From years of arguing with them, then I got a good client who was a really good termite man and we had many a long chat.

And we exposed the truths of fear selling.

I also cut down too many trees because of these termites, the same two types. The Nasutitermes usually have a darker and more round nest as depicted on the DPI site I gave a link too, however I know by scraping the channels to find the termites then ID them.

This is only for around here mate, I cant comment for say Victoria. These termites aren't the aggressive house eaters, although they can they dont.

Have a look at the tree, not much going on. They tend to eat decaying timber so will get into fence posts and the like however they build an easily seen nest off the ground.

I have been on site and witnessed termite guys put the fear into people, have trees cut down with those nests in and rip people off thousands for expensive barriers.

To this day I have not paid 1 cent to a pest controller and half my house is wood. There's enough product around off the shelves to kill termites, just spray a deterent perimiter around your house, I also drench the fence posts.

There will always be argument, but it's the termites that have no nest like that you worry about, the ones that have a nest underground or inside the tree eating the heartwood, worry about those.

So Bernard, it's just another of those fact seeking passions. If you surf around enough you'll soon discover plenty of material that supports what I am saying about these two species of termites.

If clients have a nest up the tree and continue to worry then have the nest and the tree treated/sprayed ... but you can go to Bunnings and do it yourself (confidor, chloropyrifos, merit, rogor etc). The hard part is making sure you killed them all, so maybe a bait system near the tree.

The mud galleries run down to the ground and then there's a network of tunnels the termites use. So just knocking the nest off and killing what's around is not good enough. As this is a specialist job as a professional I do request that the client get a pest controller however they need to understand the tree doesn't have to be cut down. I like to inform people so they dont get sucked in.

You do get mud nests that are not active though and birds peck a hole and make a nest.

__________________

Bernard Keays

Thanks Ekka...I’ll take your comments on board. We often receive calls about termites in trees particularly arboreal termites. There seems to be an innate fear of them. I’m not sure why as I haven’t found too many trees which have died from termites and as your photos show they don’t seem too interested in sound wood. In saying that, I would still be cautious with moist dead or partially decayed wood. All too often, people mention that they had their house treated for termites and the pest controller said that they need to get onto the Council and get something done about them. I think that if you have your house adequately protected, take an interest in their biology and apply some common sense, you haven't got too much to worry about.

__________________
Bernie

Eric Frei

Easy part mate is ID the termites. Find the mud channel on the tree, carefully scrape it open, find a termite or two, photo or into a jar with metho and get it IDentified.

Often the termites will build the nest at a point of damage or deadwood in the tree. So if a branch tore off or there's a wound they'll capitalize on it and build the nest there. Just like in the post above they built the nest where there was damage on the trunk.

For the real worry warts I have removed the nest and drilled the tree to prove it's sound.

I suppose for council if you design a check sheet for procedure and CYA you'll be fine.

1. ID the termite.

2. After IDentifying the termite select best course of action to kill them all (bait, spray, soil injection, powder puff etc ... have termite company do it and accept the liability for it )

3. Remove nest from tree, clean area up nicely so it doesn't look like a nest was there.

4. Tap test, resistograph or drill test to ensure tree is sound.

5. Document and pictures, termites are dead, tree is fine, rate payer should be happy.

For the example I had the wound was already there, such will be the case many times over. You could locally treat the wound with silica/trichoderma spray/drench to slow decay and increase tree resilience.


For the record though, I wouldn't advise every nest be killed etc, nor advise for evey resident that backs onto parks etc have all the nest killed.

The termites are an insect that serve a purpose, beside recycle decaying timber they help aerate the soil with their labyrinth of channels.

__________________

Hilly

Ekka, I spent about a year working with the line and pole inspector for an electricity suply authority. We had 2 classes of termites, those of "economic importance" and those that were "non economic". The majority of the termites we came across in power poles were of the economic variety but as a percentage of the total number of species in the Blue Mountains they were less than 25%. The rest of the species just cleaned up the rubbish on the forest floor and in people's gardens.
The one thing our inspector worried about was what he called "dry-wood" termites (of great economic importance!), those species that can live without contact with the ground. They were, from memory, established in the more tropical areas but the weather in the Blue Mountains was not attractive to them. Not all that attractive to me either, hot in Summer and bloody freezing in Winter, no wonder the termites stayed up north!
Prefered treatment was Arsenic Powder, just a puff or 2 into a working trail and the nest was dead in a month or so Total cost 30 years ago was about 50cents and no chemicals to poison the ground.
Times have changed since then.
Dennis.

Red Dot

People are over react to termites before we able to ID the species. I understand that not all termites are aggressive on sapwood.