It gets even better, Shigo used to say that someone would get very rich one day by sepersting their mulch into piles by species of tree chipped, so you'd have a pin oak pile, a live oak pile, a beech pile etc... Making sure that your mulch was free from rubbish and fungal pathogens (ie any tree felled due to fungi wouldn't go into the pile)
This mulch is then what is spread, vertically mulched ets around trees of that species. The leaves bark and wood tissues are covered in the very spores and micro-organisms that form symbiotic relationships with that species of tree, it is how the soil food web continually re-inoculates itself in nature.
Its a recognised practice in the management of veteran trees to use mulch of the same species to maintain and improve the vitality of the soil/root environment the rhizosphere. If you have a tree that you're caring for, veteran or not and you want to give it a boost without all the negative impacts of modern Nitrogen Ferts, than this is the way to go. Combined with decompaction its brilliant for trees, and results are visible for the client.
SF