HELP - How to rot away a tree stump
 

I have a Hazel tree stump.It's at least 30 years old, and the base is at
least 30 trees all fused together in a mass, which is about a metre
diameter.

Is there a way to rot this away (in a reasonable time span, months rather
than years?)

So far - I've dug a trench around and below the boll mass, cut away all the
side roots, and tried burning the boll from underneath - no joy. Over the
decades, pebbles/stones have become trapped between the trunks and fused in,
so chainsaw is not an option, (tried it, ruined the blade).

I've heard of a "trunk cutter" but access to the stump is limited, and I
fear the
aforementioned stones would preclude use of this equipment, anyway.

Ergo, only option seems to be to rot the thing away. How to do it ? Help
please ?