Your local pet store (or maybe even grocery store) should have special cleaners that can lift the smell and stain. You might need to scrub carefully between boards or in nooks and crannies. If you have a puppy, you want to clean this really thoroughly, or your puppy will keep returning to this spot.
Nature's Miracle. There is a whole array of products for dog and cat owners. The right spray will work - but may take several applications if the instructions on the bottle are followed precisely.
white vinegar is the only thing that takes out urine odor according to a dog breeder friend of mine.
Had this problem with an abusive renter. Thought I would have to replace floors. I used baking soda and vinegar. Sprinkle the baking soda on floor then spray the vinegar on top. Works like a champ.
Thank you everyone it was very helpful