Quarter sawn lumber produces nicer wood, but leads to more waste, so it is more valuable. Boards like the one I pictured above would have probably survived the 80 or so years if they had been put in low-traffic areas. But since they were in the middle of the room (there are probably 11 boards total between the dining room and living room), they wore out eventually. Here's a closeup:
Replacing boards isn't terribly complicated, but can be difficult to do without damaging adjacent boards. What is complicated, though is finding lumber to match this old, beautiful wood. The solution? Use old, beautiful wood.
It turns out that while very little South Florida Slash Pine exists anymore, there are people reclaiming it from old buildings, re-milling it, and selling it as flooring, paneling, etc. I found one such company in Fort Lauderdale, the Old Florida Lumber Company. This is a small operation with some very helpful people running it. They are going to mill up the boards I need to exact dimensions and even use photographs of the floor to match it as well as possible. So cool!
After repairing, then comes refinishing. Boy, I could go on about that for a while, but I will just say that I am leaning towards oiling the floor with a mixture of Linseed, Turpentine, and Varnish. I may even mix it myself. I really like the idea of the easy application, and should damage occur, reapplication. Stay tuned!