I really can't imagine how you're going to bury trunks of wood 2' across x 2'6 long and still have room for plant roots.
If I'm understanding your plan (doubtful). a 2' wide trunk of wood, resting on 6" of soil, resting on concrete slabs, give you a bed that 2'6" high before you add soil to plant in.
Sounds like you have a load of wood and are trying to dispose of it at nil cost.
Photos of how I used my tree at https://gardenandgossip.org/showthread.php?tid=973
If I'm understanding your plan (doubtful). a 2' wide trunk of wood, resting on 6" of soil, resting on concrete slabs, give you a bed that 2'6" high before you add soil to plant in.
Sounds like you have a load of wood and are trying to dispose of it at nil cost.
Photos of how I used my tree at https://gardenandgossip.org/showthread.php?tid=973
The Moneyless Chicken says:-
Use it up, wear it out, make it do or do without.
Use it up, wear it out, make it do or do without.
![[-]](https://gardenandgossip.org/images/zen/collapse.png)