Remove the outer bark off of the tree stump. This will reveal the smooth wood underneath and give a cleaner appearance to the coffee table.
Examine the wood slab you have chosen for the most attractive side, which will be facing up on the coffee table. The slab shouldn’t be more than around 1 foot wider than the circumference of the stump so the coffee table remains stable. You may remove or leave on the outer bark off of the stump.
Sand the stump and slab with coarse and then medium-grit sandpaper to achieve a smooth finish.
Finish the stump and slab with a wax or oil wood finish and rags, which will preserve the rustic appearance of the natural wood pieces. Follow the finish manufacturer’s recommended application procedure.
Attach a 1-inch drill bit to your drill and drill three evenly-spaced two-inch deep holes in the top of the tree stump.
Insert a 4-inch-long and 1-inch thick dowel into each hole and lightly paint the tops of the dowel pieces. While the paint is still wet, place the wood slab on top of the stump as you want it to be positioned for the top of the coffee table. The wet paint will mark the underside of the slab, showing exactly where the holes need to be drilled in the underside of the slab.
Remove the slab and turn it right-side down. Drill three 1-inch-wide and 2-inch deep holes at the points marked in paint.
Remove the dowel pieces and coat them in wood glue before returning to the holes in the tree stump. Sit the slab on top, with the holes in the underside of the slab mating with the dowel pieces.
Weigh the slab down with heavy books or other heavy items while the glue dries and then position the coffee table as desired once the glue is dry.