So lets look at the autopsy of this mango tree, and compare it to what you might have had in your minds from the beginning.
And the final low stump cross section
Some interesting boundaries in that one! Remember the greatest problem for this tree despite appearances from those pics is not the failure of the stem, there was plenty of solid new timber there....no for me the issue is the loss of buttress roots on the only side of the tree unaffected by the footpath and kerb and road damage all on the other side. The high value targets make any assessed problems far more significant than would be the case in another tree.
But remember the first pics of the small fruiting body, except for the depression in the stem there was no other visual indicator above ground, the canopy of the tree was pretty much normal for a
Mangofera in such a street environment.
Without doubt the automatic irrigation system with a popup sprinkler near to the stem increased the propensity for fungal growth to progress rapidly...for us Ganoderma australe, G. lucidium, G. applanantum, Phellinus igniarius are our worst root and stem problem fungi. We take great care with our tree inspections to follow a systematic approach to recording all visible indicators trying to ensure that in the trees we look at we won't miss even the smallest sign, helped by the fact that serious fungal decay in our tree species is almost always indicated in more than one way.