Cleaning and Stain Removal - Water stained wooden floor

When I discarded my Christmas tree which had been sitting in a stand holding water atop a small carpet on my oak tile floor, I was horrified to discover that a 3 foot ring of moister had collected and mildewed there under the carpet. Although I had done this same set-up for many years without problems, disaster struck this year and I don't know how to get the discoration off. The tiles are now dry by way of a heater for 36 hours and I had no trouble cleaning off the mildew. What I have are darkened oak tiles in a three foot ring. The tiles have never been varnished or otherwise coated except with products like Pledge. Help, please. What can I do myself?

Unfinished wood has nothing to protect it from moisture. The stain, if it has not penetrated deep into wood, may possibly be sanded out. Sometimes wood bleach can lighten stains on wood. Some camouflage stains by staining wood a dark color. In some instances it is possible to replace affected area with wood removed from an inconspicuous spot such as a closet.

Floor should be sanded and sealed for protection. Pledge is not recommended for wood floors. It contains silicone and can dull and soften floor finishes over time. It also does not provide adequate protection for unfinished wood and can cause adhesion problems if staining and finishing.