What I would like to do is use this thread to stimulate thoughts in all of you as to just how you go about assessing (where visually present) fungal decay in trees you are asked to look at/work on.
Its not about how clever I am, or Ekka is, its about looking at some visual examples and talking through what each of us thinks about different approaches. If you don't want to post a response fine but at least think through what is being discussed and how you might have approached it and why.
(Some of the photos I'll use are from a while back and one or two may have been posted in other threads)
The first case study is of a mango
Mangofera indica groing in a fence line at a kindy next to a main street that has very high volume traffic usage. The tree is approx 50-60yrs old, 13m high with an asymmetrical spread of 11m. I was conducting a base line audit of the trees in this school for a tree management plan.
At the base of the tree where the ground level meets the bark was a small fruiting body of the fungi
Ganoderma sp 
Here's a better shot also showing a classic depression in the stem spreading up from the ground in the shape of a rough triangle.
So sounding the stem also confirms the same conclusion altered state in the wood tissues in the indicated area.
We know Ganoderma is a fairly agressive root rot fungi, so strongly suspect that the root system on the knidy side will have been compromised. The root system on the footpath and road side certainly has been!
The tree is providing substantial valuable shade to the grassed playground of the kindy area, but this also means that very high value targets are present under the canopy of this tree as well.
Now remember schools have slightly more capital resources than private tree owners (generally!) and have a much higher commitment to the Health and Safety of those under the canopies.......so given that we have no resistograph, and I have no faith in pico's our next logical step is to do a root crown inspection to assess just how much of the root system has been compromised.