Couple of comments. I hope you guys are young! For a white oak to get to a really nice size, say 30-36 inches across the stump, it will take at least 80 years. Walnuts will probably grow a bit faster, especially in bottom ground that drains okay. My advice, be the woods. Ie., create diversity so that whatever insects/diseases invade and kill one group of trees over the next 40 years, they don't wipe you out. Mother nature seems to know best, most woodlots are extremely diverse, although there may be clusters of one tree type in small areas. We can learn a lot just by paying attention to how nature works on its own. I've also heard people who plant trees knowing they will never live to profit from them are generally optimists! I agree with that. On the other hand, I will live to see the wildlife benefit from them and that is good enough for me.