I believe that you will need to take off the bark if it is not yet removed. this can be done with a hatchet, chisel and hammer...and is really fun. If it dries too fast it can crack and there is some formula regarding the thickness of the stump and how fast it will dry.
Margaret, the important thing to do is seal both ends of the wood so they don't crack. You do not need to take any bark off - some people use that - it's OK. The easiest way to seal the wood is to paint it. Make sure the end is completely covered with a heavy coat. Then set the wood aside in a dark, dry corner of your studio. It is important to keep it dry. Depending on the width of the stump, drying can take a very long time. Have fun with it.
Hi Margaret, I happened to see your question posted and agree with the comments in reply. In addition, I might add the following: I don't know if the stumps just came out of the ground or you found them on a beach, but the easiest way to clean them up is to power wash them (great for removing bark if necessary). Wood drys to furniture making conditions at about 1 inch per year. Fortunately, you don't need to worry about that kind of dryness if it is used in your shop as a solid base/table. Make sure it is clean, bug free and looks dry to you. It needs to be stored up off the ground during your drying process so air can circulate underneath. You don't want fungus growing in warm, wet conditions. Once you move it into your studio it will probably check of crack which will not really compromise it's integrity or strength. If any particular crack opens enough to bother, you can tape up the side and fill the cavity with epoxy sanding the top smooth again. Good luck with your work. Ron P.S. If the stumps came off the beach it is very important to power wash first before using power saws to shape them as sand embedded in the surface quickly dulls the blades.