I am somewhat of a neophyte at making natural edged bowls. I recently was given a whole Bradford pear tree and feeling flush with raw material, I was persuaded to take some risks I do not ordinarily take. As you hollow the bowl, part of the time your gouge is floating in the air. It takes a lot of tool control to keep from knocking off the fragile bark on the undulating rim.
This tree was cut in September when it was still full of sap. I found that Bradford pear sap is like glue and I would have to frequently change band saw blades to get the wood cut up in proper dimensions for turning. Well, that glue set up and made the bark unusually adherent so that it made for more allowances of imperfect technique than any other natural edged bowl I ever tried to turn.
The bowl was turned green to final dimensions, and sanding green wood does not work. Furthermore, trying to sand a fragile spinning undulating rim was just too scary for me. This meant that there was much more hand sanding in the finishing process after the bowl had completely dried. Wherever you have figured wood it dries with a very uneven surface. Here I used my cabinet scraper to good end to remove wood faster than hand sanding. I was surprised that the bowl dried without checking and with very little warping. It was most noticeable in the base which would not sit firmly on a flat surface without some attention from my carving chisel.
For finishing I applied and sanded out a couple of coats of de-waxed shellac and then finished with a coat of tung oil. I read recently that de-waxed shellac is compatible with any other kind of finish applied over it. This sealing of the grain prevented the tung oil from penetrating so deeply that it would take months to dry completely. I was satisfied with the finish which had not even been waxed yet.
See this bowl in my bowls gallery here.