The maintenance plan helps to protect the new growth to be eaten e.g. by moose and elk.
This is in Eastern Australia, where we have native wombats, macropods, possums, as well as wild/feral pigs, goats, rabbits, and the occasional deer, along with parrots and fruit fly that tend to destroy fruit with potentially viable seed. But at least we don't have moose, I guess.
Fencing off an area to stop the ground-based pests has impressive observable results even after a couple of years - but it's very expensive, and fences decay within the lifetime of many of the pioneer trees.
So de jure reforestation, while a nice principle, isn't feasible in all environments.
Further complication in many areas desperately in need of reforestation is periodic drought -- Australia and the Americas have the famous El Niño / La Niña cycles to contend with, where we regularly have several consecutive years with minimal (or at best unreliable) rainfall. Again, this is an excellent candidate for a very cheap mass seed distribution system that can simply be re-run each spring until a favourable rainfall pattern produces a good result.