If you want your table top -- any table top -- to actually ast without bowing/cupping/twisting, you MUST attach it in a manner that allows for seasonal wood movement. Wood is an organic product, and it naturally expands and contracts with changes in temperature and humidity. I'll post link below to a couple of options that you can cheaply buy which will allow you to securely attach a tabletop while still giving the wood the flexibility to move with the seasons. When you buy decently-made furniture at a store, they all accommodate for this one way or another. Don't just screw the top down to the legs or the skirt...you'll regret it later on.
Slice, dice and serve in style on this easy, attractive board. We’ll show you a simple way to dry-fit the parts, scribe the arc and then glue the whole thing together. We used a 4-ft. steel ruler to scribe the arcs, but a yardstick or any thin board would also work. Find complete how-to instructions on this woodworking crafts project here. Also, be sure to use water-resistant wood glue and keep your board out of the dishwasher or it might fall apart. And one more thing: Keep the boards as even as possible during glue-up to minimize sanding later. For great tips on gluing wood, check out this collection.
Just redid my dining room table with this technique and I an observation/suggestion others might find helpful. The boards did not line up well putting it together upside down, even on a flat concrete floor with me standing on the boards while they were screwed. I would have combined biscuits with the pocket holes to ensure a better alignment of the boards. Lots of sanding was required after assembly, and this might not be a huge deal with pine, but I used hard maple so it was quite a chore even with a belt sander. Also, be aware that the 1x2s around the edge may not line up perfectly -- I had to trim about an eighth inch from each side after assembly to get nice smooth, even edges. Not a big deal, but the top turned out a little smaller than the specifications I was give by SheWhoMustBeObeyed. Otherwise our table now looks great, and thank you for the post!