Rot and substrate selection

I was offered a bunch of wood cut from this bigleaf maple stump to use for mushroom inoculation. While I love free wood, my instinct is to avoid maple trees that have rot in their hearts, there is often rot in their limbs as well. (When the main trunk has rotted away and been replaced with a number of spidery lateral trunks.) This established stuff must be competition for whatever I want to inoculate with, right?