Sorry, I failed to mention this would be prefinished flooring.

Do you have a way to control the humidty in the home?
If you can go with which ever species you want.

If not then just beware that any wood is going to absorb moisture.

Hickory can have different color variation. But if $ is not an issue just have whoever is installing to take out unwanted boards.

Most places suggest 3/4 in plywood. But if you 1/2 in is in good shape you should be okay.

Also allow the floor (which ever type you choose) to acclimate inside the home for a week or two. If you dont and just install it. The wood can go into a state of "shock" and quickly warp.

Thanks so much. We have decided to go with the Lyptus.

Humm! NWFA Guidelines state minimum 5/8" thickness plywood exposure 1 to nail 16" on center, 3/4" Tongue & Groove between 16" to 19' or 24" spacing 7/8" T&G. you may nail another 1/2" exposure 1 grade over the existing.
Regarding moisture content make sure your installer has a moisture meter and measures the subfloor and wood. Wood is mfg between 6% & 10%. The subfloor cannot have a mc higher than 13% or whatever the mfg says. There cannot be a difference of less than or more than 2% between subfloor and hardwood moisture or you may experience gaps or buckling between seasons. I.E. Moisture guide states 8% to 11% would be the ideal range in Virginia therefore 10% would be in between and ideal. Wood MC = 10% subfloor no more than 12%. This information is available in every box or website for each and every mfg. Sitting the wood in the house puts it a what is call Equilibrium Moisture Content BUT testing moisture content is the only way to determine if it is ready. Kind of like baking a cake in the oven at 400 degrees IF you don't have a therometer how can you know if it is time to insert the cake. Answer you don't! Find an installer who understands the science of wood and has a moisture meter. Or you may need a wood inspector to explain why the floor is buckling, cupping etc. As an inspector all I ever see is failure oh yeah please keep your humidity levels in the home at the level recommended by the mfg or you have no warranty. GO TO WWW.NWFACP.ORG AND UNDER CONSUMERS FIND A CERTIFIED INSTALLER IN YOUR AREA IF THE PERSON SENT TO INSTALL YOUR FLOOR DOES NOT UNDERSTAND WHAT I POSTED ABOVE.

Hello,

I noticed you installed Lyptus flooring a few months back. We are seriously concerning this type of wood for a flooring option, we found some stranded Eucalyptus flooring from an Austin company call HardwoodBargains.com. It is has been very difficult to find many reviews on it. Is yours solid wood or engineered? How do you like it, has there been any problems, such as gapping, warping, etc? We live very close to the ocean and in a humid part of the country, so stability of the wood is important.

scottyb did you decide on lyptus and how do you like it/how has it worn? we are trying to decide between bamboo and eucalyptus. thanks.