height = 7
bone = 2
tree = 1
wood = 4
function plant()
  turtle.select(tree)
  turtle.place()
end
function destroy()
  turtle.select(wood)
  turtle.dig()
  turtle.forward()
  for i = 1,height do
    turtle.digUp()
    turtle.up()
  end
  for a = 1,height do
    turtle.down()
  end
  turtle.back()
  turtle.dropDown(64)
end
function one()
  turtle.up()
  detect = turtle.detect()
  turtle.down()
  if not detect then
    if not turtle.detect() then
      plant()
      turtle.select(bone)
      turtle.place()
      destroy()
    else
      turtle.select(bone)
      turtle.place()
    end
    turtle.down()
  end
  destroy()
end
while true do
  one()
end