As timber dries out it naturally shrinks across the grain. Good design in wood makes allowances for this - door panels and drawer bottoms for instance are usually fitted without any fixings or glue. Similarly a table top should be fitted so that it can contract or expand in width and not be fixed too rigidly to the base. Changes in humidity can affect the wood and cause splitting.
There may be no permanent fix for your table. You might do well to examine how the top is attached to the base and arrange if you can to accommodate any further shrinkage. Look for screws in slots that allow for movement - they may be too tight.
If you soak the table the grain may swell and the cracks disappear but as soon as you bring it back into a dry environment the cracks will reappear. Filling the cracks may seem like a good thing to do but you can never be sure that the cracking has finished - filled cracks may reopen.
Peccavi, December 2008
