The main problem with volunteer planted tree planting projects is people don't know how to plant and care for a tree, they are not horticulturalists. The reason the food forests you mention that are ancient exist is because those ancient people lived outside in nature growing their own food and were experts on planting and caring for plants. Most often, as a professional market gardener/farmer, I cringe when I see the majority of people planting things, even those who claim to have experience with gardens, and the massive mistakes I see made constantly on homestead level projects. It is like this, you can make one or two mistakes and a tree will still grow, but as soon as the mistakes start piling up on top of eachother, the long term prospects of a plant of any kind goes way down. It has gotten so frustrating that I hardly even try explaining to people anymore unless they are really open to advice; somehow gardening is the one subject where people who don't do it full time really struggle to understand that they could possibly know less than someone who works with plants all day every day.
Just as a small example, you will constantly read "prepare the soil one year in advance with compost, lime, other amendments and cover crops," yet how many people just show up the day of and dig a hole straight into sod/old pasture? Have you ever seen how long it takes trees from the edge of pastures that are self seeded to struggle for many years against heavy sod growth before transitioning to a woody ecosystem, besides things like willow, aspen, blackberries etc.? It will be decades possibly before you get a tree of any height when things are left to their own on degraded pastureland, possibly never depending on the distance to bedrock/water table/a million other factors. And these are native trees, not fruit and nut trees with even higher requirements. People love to go on theoretically about ecosystems and how land regeneration functions, has anyone actually ever looked at it, or does everyone just read the same books that give a nice fairy tale picture of how land goes from pasture to scrubland to forest, completely ignoring what actual reality looks like?
I have seen people do really dumb things when planting trees. Mixing half clay with half fresh manure and soaking the roots in this mixture, shoving all the roots down into a hole in a bunch and not compressing the ground, wrong height in the ground, planting trees in wet spots, planting too old of stock, planting potted plants that are rootbound... there is an inumerable number of errors an unskilled person can do when planting something. Not to mention somehow people seem to think a degraded pasture that can hardly grow grass will somehow magically feed a conventionally grown 3 year old fruit tree.
Its not hard to learn how to plant things, but a person must come in with an open mind and be willing to learn, I have planted thousands of trees but am always happy to meet someone new that actually knows what they are doing and has a pointer for me. Normally people with a 40 square foot garden come into a volunteer day and assume because they know how to (poorly) use a spade they will be fine.
Give me a volunteer labor force in June to weed around the trees, cut off diseased branches, spray with things like whey, spread compost around the trees etc. any day over a volunteer planting force. I have given up trusting other people to plant anything unless I am certain they have some commercial or very serious hobby level experience; planting a bunch of trees doesn't take so long and I'd much rather take my time over a couple weeks in november alone and ask volunteers to help me in the summertime to actually care for the things.
