Inner ring MUST have a layer of large river stones for air +water to get to trunk, otherwise it will suffocate + kill the tree. The soil will support small shallow rooted plants like Allyssum or Primrose.
Last Autumn, the trees in our front and back yard were trimed ,so we got some logs. Its very waste to throw it .we got idea from website to build planters for our garden plants from it. Log Planters are a Natural Addition to Any Yard Log Planters make use