Answer to my own question... This is certainly cutting edge stuff figuring out what going on at the fungi level... No one really cared before, except the Ganja grower, so little research has been conducted. C>N are in partnership in this process..
Symbiosis with ectomycorrhizal (ECM)
Trees deliver a significant portion of their photosynthetic carbon (C) to the fungi. This nutrient exchange affects key soil processes and nutrient cycling, as well as plant health, and is therefore central to forest ecosystem functioning. Due to their ecological importance, there is a need to more accurately understand ECM fungal mediated C and N movement within forest ecosystems such that we can better model and predict their role in soil processes both now and under future climate scenarios.
Symbiosis with ectomycorrhizal (ECM) fungi is an advantageous partnership for trees in nutrient-limited environments. Ectomycorrhizal fungi colonize the root...
www.frontiersin.org