Vman may be correct, depending on your age. However, tree growth has as much to do with resources available/growing conditions as genetics. First things first, get a soil test. Its not hard, dig up some dirt from the area you want plant and mail to ISU with 20 bucks and that will get you started.
The best return is to find 20-30 year old straight veneer potential trees that do exist on your land and free them up. 2nd best thing over planting some is to open massive amounts of canopy for those same veneer trees to reproduce & regenerate new growth, which actually they probably have started to as well. Open things up and free those rascals up immensely.
BigfootWillow.com
Tree Climber
Also read up on thousand cankers disease. This is killing black walnut trees and spreading throughout the united states as time goes on. So I wouldn't get too excited about planting a monoculture of Black walnuts, diversification is key. http://thousandcankerdisease.com/
Yep, know all about it. I will prolly do a direct seeding of oaks, walnuts, and others, if nothing else for deer cover. Right now i am doing nothing with it.
Diversification is actually really beneficial for walnuts anyways, fast growing competing trees make them grow straighter. I've seen a lot of walnuts planted but really the best trees are going to be in existing timber that requires them to fire straight up. Get through every drop of your timber and baby the living daylights out of every veneer possible walnut 5" to 20" and even release the mature trees and you'll be in amazing shape. And another 2 cents, I will not touch a veneer walnut tree until it's 25"-26" DBH. A lumber grade tree, I'll start those at 19". Unless they are crowded or on a creek bank & will fall in. Baby those things! Oh, as you do TSI, prune the branches off you can reach and cut the vines off.
yes, a diverse woodland is great!