I had lots of wood logs used as the garden beds' borders. After a couple of years they were half rotten.
Rotting = lots of bugs including worms underneath - good for the soil eco system…
But on the down side, this attracted critters at night (armadillo?) that love digging around the wood. It seems that in the garden there are new challenges every year - dealing with the world that discovers the garden (squirrels and others). I need a night camera to see what's going on when I sleep!
So I finally decided to change the borders of two backyard beds - using metal sheets (left over from the roofing project) and cement blocks.
The visit of Dave's garden (a friend from permaculture class) inspired me to build a hugelkutur bed to use the rotting logs and the old pile of wood chips in the front yard, sitting there since last April (some had turned into very back soil). Here is the result. I put some compost on top and could not resist putting a few plants straight away. Will be fun to see how it works out in drought period!
Here is more of the theory on these types of bed! http://www.richsoil.com/hugelkultur/