We do
hugelkultur in the subtropics with felled banana
trees. It's not true wood, just fibrous vegetation in log form but it works beautifully. The logs are already saturated with
water and they release it as they break down which usually takes only a few months, on top of the logs we place dried banana leaf
mulch then top with composted
chicken manure and some soil. I plant seedlings directly into that and so far, nothing has died. In fact everything thrives. We've also used it for bulbs that need free draining soil which we cannot put directly into the ground because the property periodically floods. They are also thriving. This block is lowland coastal flood plain, the ground level is low and boggy often. The ground water is only a few feet below the surface so water isn't free draining. Using this method allows us to grow things that typically wouldn't survive the heavy rains.