Three years ago I had 2,200 trees planted in about 3 hours. Certainly not by hand! He used a JD tractor with a tree planter attachment on the back and sprayer on the front. Sprays a 3' wide swath with Oust to keep the weeds down until about mid July in the rows, but then it peters out and the weeds grow anyway. Not much you can do, and I sure as heck ain't gon'na trim around all those trees.
So far I would gues that I've lost less than 2%, most of them by me mowing them off! I mow between the rows with a bushhog about 2-3 times per summer to keep the weeds down, and it can be hard to see those trees and I get too close to them. Last year was dry, and the spray kept the grass down, but the Mare's Tail was terrible, and hid all but the tallest trees, because this stuff grows about 4-5' tall.
They are planted in 10' rows, every 8' apart. Every other row is white pine and the in between rows are a mixture of hardwoods, mostly black walnut, red and white oak, tulip poplular and cherry. The idea, according to the DNR, is that the white pines grow faster forcing the hardwoods up towards the sunlight to make them nice and straight, but after about 40' the hardwoods top the white pines, shading and killing them, in oh about 25 years or so. By this time the hardwoods are tall enough to create their own competition, and grow straight and tall on their own. I guess in about 25 - 30 years there will be tons of firewood if someone wants it because of all the dead white pines.
I have this in a CRP program, and the gov't pays me a little bit to not farm the land and they paid for ~2/3 of the cost of the trees and planting them, which was about $1,200. The trees came from the DNR, and mostly were about 3 years old, as I picked the older trees so they would be larger and stronger and more likely to survive, albeit a little more expensive.