Hello,
Can anybody tell me what type of wood this is? I initially thought it was pine, but then someone told me most of the houses in the area were build with hickory.

Backstory - We we’re going to repair some water damaged 3/8” oak in our 100 year old home. When we started to pull the bad pieces up, we realized we had the original floors underneath that match the floors on our second story. We have now opted to refinish the original floors so they match throughout the house. Interestingly the flooring under the oak, is unfinished.

Unfinished floors under our damaged oak.
https://share.icloud.com/photos/0AdLw7y ... #Frankfort

Finished floors upstairs
https://share.icloud.com/photos/0CsfhjV ... deTNQMEVOQ

Finished floors upstairs
https://share.icloud.com/photos/0k3Q0M5 ... #Frankfort[/img

Here are working links to the pictures.

Unfinished floors that was under the oak flooring.
https://ibb.co/fC3Cr3w

Finished Floors Upstairs
https://ibb.co/HTJss2N
https://ibb.co/Hr1R9h3

You have pine flooring. It is much softer than any oak floor. The upstairs floors are plain sawn. Sometimes these floors are covered with a poor man's rug.
The best pine floors will be vertical grain. This is like quarter sawn oak, where the growth rings are close together. The harder part of the grain will protect the softer part from denting. I recommend three coats of poly-urethane be applied. You may need to install base shoe molding next to the walls. Apply the base shoe with finish already applied before the final coat of finish so once you get the floor perfectly clean and apply the coat of finish you will be ready to move in when it has cured. Of course the floors ought to be the last thing, just before the wall paper, if you are decorating.

We jokingly refer to this as subfloor as it is laid directly over the joists. It’s usually cheap pine and can be refinished , Just don’t sand to hard.