That's where they're meant to be. Provided that they aren't near the house or the tree won't fall on the house, it shouldn't be an issue. They can travel 50m from their base so treatment may consist of baits If deemed required.
My thoughts have always been to eradicate any termites on the property, assuming it's not some sort of acreage. Have you spoken to a pest controller about a way to exterminate them?
Or, if you want the cheaper route, you can get some stuff from Bunnings to spray them with. We've got some in the yard of a property that we're doing stuff to. We'll be spraying all around the yard, just to be sure.
