Greetings Daniel,
Okay, where to start :-)
First, I would like you to contact your local forester with the Arkansas Forestry Commission for on-site assistance. Your local forester will be able to determine whether or not your location is a "prime" black walnut site (via your local soil survey). Optimum black walnut growing conditions require deep, fertile, moist, well-drained soils. Nothing beats local, expert experience when it comes to forestry!
Secondly, here in Illinois we typically afforest new sites utilizing 436 trees per acre (10'x10' spacing). We machine plant probably 95% of new tree plantings in Illinois. I have a lot of experience using 1-0 planting stock which will run you about $0.30-0.60/tree for 18-24" tall bareroot seedlings. The Arkansas Forestry Commission may have a state nursery and financial incentives to help you in your endeavors; again, check with your local AR forestry office.
Overall cost analysis (IL Example):
Trees (436/acre) = ~$218.00/ac
Machine Planting = ~$100-150/ac
Herbicide Control = ~$30-60/ac
On high-quality sites (i.e., good fertile soils with proper texture and drainage), you can expect a reasonable rotation age of 40-60 years for eastern black walnut; 60-80 years for average sites. Of course, this requires some maintenance and active management on your part to nurture this crop to economic maturity :-)
Overall, there are some variables to consider and there is no such thing as a cookie-cutter answer to some of your questions. Just remember to call your local AR forestry office in order to get you started in the right direction!
Best of luck to you!
