Previous comments pretty much summed up tree planting...it's a tough row to hoe to do it successfully.
Two key elements IMO...herbicide for grass/weed control and fencing for ALL hardwoods and conifers other then red cedars.
Try fencing 2000 spruces....not saying it can't be done but it entails a lot of work and expense if you can't come up with enough old rolls of woven wire to do the trick.
Like everyone else...I got tired of "fighting" it and switched over to red cedars and plant just a handful of hardoods, fruit trees etc. each year that I can handle fencing for.
I've had bucks rip the gro tubes off trees and then mangle the trees...so nothing is a sure bet with out fencing.
Without herbicide the trees will grow slowly or have a high mortality rate, although mowing will get you by.
The packets themselves are just tree/shrub combos but you can order specifically what you want. There are many other places to order seedlings and I have had some problems in years past with the State Nursery stock...one year ALL the pine seedlings died that everyone purchased. Apparantly (at least at that time) they used prison labor to help and at lunch time they just dropped everything...and left thousands of bareroot seedlings in the sun to die (that's what I was told anyway..... /forum/images/%%GRAEMLIN_URL%%/confused.gif )
Planting trees is something I have been doing for 40+ years and my Dad and Grandfather did it before me. It's a great feeling years later to see those trees maturing someplace that was once an open field. Just plant the right trees in the right way for your area being aware of all the problems that can arise.
Read thru our
Tree Planting thread for lots of advice and helpful information.