Al Kaline it will be fine to use as surface mulch, then the wood will hang around on the surface & decompose in air.
Yes you could plant into that. say no more than 3-5cm/1-2in deep.
I would not use it to make a new bed of say 15cm/6in because then there is wood in the rooting zone, where it takes nitrogen to break down, to the detriment of growing plants.
