Q. How can I protect the wooded from in my raised garden bed against the moisture from the soil?
It is inevitable that the wood eventually will begin to rot. However, you may use a pond liner against the wood to stall the process. Treating the wood would be dangerous to vegetables if that is what you are growing. It might be better to let the wood rot, and then build new raised beds with hemlock which is more resistant to rotting, or with plastic wood made from recycled bottles, which can be expensive. Good luck.