Great pics Ekka, and a great find considering the recent events there..again clear VTA indicators of severe problems high value targets yet little action. But lets focus on the fungal decay, maybe drawing a long bow but I can convince myself I see a depression in the stem above the fruiting bodies, looks like
Ganoderma sp to me too.
So what action if the council had been proactive enough? For me root crown inspection, its cheap quick and answers nearly all your questions. When you know the id of the fungi you can apply your knowledge and understanding and experience as to how this particular fungi interacts with this species, combine the environmental factors, the current health and vigor and really begin to be able to predict with confidence what the possible outcomes will be.
They really are great shots mate! They tell a very different story to the one in the media.