My daughter, Catherine, saw some of these birch logs in a wood pile at a friend of theirs. Catherine talked them out of a couple of the logs just because she thought they might look neat for some type of project someday. I had the same thought, so I snuck one home one day to make a flower pot out of it.
I used a 1 ½” forstner bit to chew out most of the wood.
Then with a 2 ½” hole saw I smoothed out the perimeter.
Then back to the forstner bit drilling deeper inside.
The last step was to use a 12” long ¼” drill bit to drill some drain holes down at an angle, for the water to weep out the sides of the log.