I have personally planted somewhere over a million seedlings everywhere from SE Alabama to NW Alberta, while also supervising the planting of a couple score million more by planting crews.
Any questions on seedlings of any species just ask. But the answers will vary by species.
Investing in a Walnut plantation is an occasional topic I get asked about but few ever pull the trigger on doing it. If you do, just make sure your heirs understand that Walnut goes through peaks and valleys in price as its wood goes in and out of fashion in furniture markets. Black Cherry goes through the same process and currently ends up at the pallet mill as a result. But as long as people holding a large quantity of one species understand that and have current aid on spot timber prices from an independent Forester (not a mill buyer who calls themselves that), they can wait out periods of species specific low prices.
For Black Walnut in particular I suggest a 2 species plantation - a secondary species such as White Pine is used in alternate rows as a ‘trainer’ type tree to create the density needed for self-pruning to create high quality sawlogs. These rows are removed later, hopefully in a pulpwood thinning. Planting rows of only Walnut might be counter-productive as you wouldn’t want them as pulp and their seedlings would be much more expensive. A different option would be to plant at a lower density and then invest in manual pruning ten years in, without worrying about thinning.
State Ag Extension Agencies in the Midwest would have more useful specifics; some states such as Indiana have Walnut Improvement projects going for plantation purposes. I do not know how Walnut works in the north-east but I would research this carefully. Walnut would struggle on the wrong soil types.
For Black Cherry, I would simply invest in pounds of clean seed and plant that, and at pretty high densities. Pennsylvania used to have Improved Black Cherry but I am not sure if that is still a thing.
For any planting idea, first consider what will happen to a given site if you do absolutely nothing. Is there a big White Pine or Black Cherry already standing over it? Is there already numerous tiny seedlings of those sprouting up naturally? Probably so. Sometimes the first thing you have to do on a planting project is to kill all the trees already there. Wait, what? I can’t even tell you how many planting projects ignore that obvious common sense about natural regen. That is because they are often designed on computer screens by -ologists of various types.
As for asking a “Forester” for advice, be careful there. Most with a Forestry degree go straight into procurement work and never look back. They don’t always understand the nuts&bolts of a planting project, because they don’t have to. They largely manage naturally regenerating forests, with some exceptions in conifer plantation systems. That leaves public assistance folks in Conservation Districts or NRCS offices. Some of those peeps are very smart and experienced with tree planting, generally the older ones. Others have a degree in Ecology or ‘Natural Resources’, whatever that is, and only know the nuts&bolts of planting trees from cutting and pasting instructions from other documents, and can often be as lazy about ground truthing this stuff as my planting day is long. That leaves nurseries, who will tell you a mix of what you want to hear, and favorable things about what inventory they most need to move, as seedling supplies are essentially perishable and unsold stock can’t just sit for an extra season like a rack of 2x4s can.
As for size of stock to plant, there is often a dizzying array of too many choices. I sometimes kid nurserymen that there is really only one size a majority of customers want - “biggest.” This is because most people aren’t planting very many trees, and can easily water them later. But when the project is measured in acres, seedling size has a dramatic impact on project costs in time and money.
A general rule of thumb is to pick the middle of 3 size choices. Bigger stock will survive less in a dry summer, and acres of seedlings can’t always be watered efficiently (it can usually be cheaper to replant than attempting large scale watering). Stock too small might be too easily de-leafed by insects or other animal damage and not have the root reserves to overcome that.
With deciduous species, what you are really planting is a root system. Tall deciduous stock might die back from the top and grow new shoots out of the root collar only in a dry summer anyway, as the young seedling attempts to re-balance it’s root and leaf systems in it’s new home with no sprinkler watering it routinely. Most southern nurseries sell only one size of hardwood stock - pruned back to a uniform 18”, for that reason. With Oak seedlings in the north, I often top prune them some before planting and get better results later on.
Walnut in particular can often be delivered a bit over-grown, with incredible tap roots quite difficult to plant. Public nurseries often offer them that way, as Joe Farmer planting a bundle of 25 seedlings only wants “biggest.” Too-large seedlings result from low quality seedlots and other poor cultural practices resulting in too much bed space per seedling.
So you want Walnut for a large scale project from a smart nursery that cares about the fine details, which publicly subsidized nurseries don’t need to care about. In the Midwest the best Walnut I have planted is from Alpha Nurseries in Holland, MI. In the south the large chain ArborGen grows a good plantable Walnut; they sell to large projects that need reasonable planting stock, not “biggest.”