Gum tree roots and toilets. In Australia these do not go well together. We discovered much to our horror that the roots of these trees can travel simply miles underground in search of water especially in droughts and they often find pipes to invade. Sadly our suburb has them planted 2m away from the main pipe and therefore you land up with a portable loo in the middle of winter. Gum trees are good for koalas that eat their poisonous leaves, for birds but not toilets and every Australian knows this at some time in their life. This is the reason we value plumbers highly in Australia.