Hugelkultur Problems

I started some Hugelkultur beds near some trees and now 4 months later most of my trees are in decline with growths of armillaria -- I'm assuming from the dead wood I've buried. This is occurring all over my yard. How is this avoided?

What kind of trees are they, and what kind of wood did you bury? Also, how close is it to the trunks?

Any kind of dead matter should be kept back from tree trunks somewhat.

It's an extremely diverse set of trees: 2x Jacarandas, a Lychee (dead), a Triangle Palm (dead), a Queen Palm (dead), a White Sapote, 2x Gumbo Limbos, and 2x Avocado trees. I live in Central Florida zone 9b. I buried all kinds of woody material in the ground around each plant, not directly under or anything like that but fairly close to the rootballs.

Most tree roots are in top soil, not good to dig around and introduce material that need breaking down, it uses stuff.
I try to avoid burying anything around trees, just drop it on surface instead and not to close to trunk as already mentioned.