[WastedCucumber]

IIRC, communication of threats, exchange of rarer nutrients (this is the main symbiosis trees have with the mycelium anyway), perhaps from healthy trees to needy trees. Solething like that? If I find a source I'll edit this comment.

edit: turns out the Wikipedia page is extensive.

https://en.wikipedia.org/wiki/Mycorrhizal_network?wprov=sfla...