Let me frame an answer a different way:
It's not how many plants you are growing, but your succession plan. In most climates, you can get at least 2 crops in during a growing season. Where I live (zone 9b), I can grow year round. In the winter cold months, there are always greens like kale, spinach, cabbage and other brassicas. In the summer, all the regular warm-season veggies. Perennial greens like moringa and chaya produce well in the summer. We get all manor of squash and sweet potatoes all year.
So the key for us is to plant something EVERY WEEK. If I'm not starting something every week, I'll run into a food drought in about 2 to 3 months. Every Saturday I'm out scouting for a new space to drop a couple of seeds into the ground, or I'm potting up new plants in my little nursery.
Then, throughout the year, I don't let plants grow to the bitter end and die of natural causes. Once a tomato or squash has peaked and is starting to decline, I've already got a new baby plant growing nearby. I won't keep a plant until every last single tomato has been harvested, but I'll cut it down and use that space for something new. Just because there is one or two scrawny peppers still growing on a tired old pepper bush doesn't mean that it needs to continue to take up that space.
When selecting fruit and nut trees, don't just look for the most productive trees in your area (10 trees all of the same variety) but pick a variety of trees that ripen in succession. I've got 5 peach trees, all of which ripen about 2 weeks apart. I have fresh peaches from the end of May till the middle of July. We have apples from May till November. Avocados from November till June. You get the idea. We get a lot of fruit (particularly stone fruit) in May and June, but there is something ripening out there 12 months of the year. Apricots, plums, pluots and cherries in the spring, apples and figs in the summer (when we've also got watermelon and other vine fruits), apples, pears, asian pears, pomegranates, figs and persimmons in the fall, and citrus and avocados in the winter. Every week of the year, we are picking something off a tree and eating it.
And throughout the year, there are veggies growing underneath all those trees, one crop after another.
All this does a couple of things:
1. It produces a LOT of biomass, which we need to continue to feed the system. A new compost pile is constantly being built.
2. It keeps a constant flow of dying plants and spoiled food for the chickens. The girls always have something to peck at and eat. They turn all that biomass into eggs, meat, compost and nitrogen rich
poop.
3. It keeps a living root in the ground 12 months of the year, thus pumping life into the soil. We don't worry about overusing our soil, as we are constantly re-mulching with wood chips, constantly top-dressing around plants with compost, and constantly rotating our crops.
4. It maximizes micro-climates. In the winter when leaves fall from the trees, we plant greens and plants that don't like too much sun. In the spring, as the trees bud out, it gives salad crops and herbs a couple more months of shade before the hot summer sun makes it too hot to grow them (and by which time we are growing them on the north side of the house where it's much cooler and shadier).
5. It's always visually interesting. There is always life in the garden in some stage of succession—early growth, fruitful production, or seed production and end of life. From month to month, the garden is in a constant state of change and succession.
6. It maximizes the space. I can get at least 4 crops off any given space in my garden/integrated food forest throughout the year. It might be a cover-crop for winter, but something is ALWAYS growing out there.
7. There is always food "stored" out there: beets, carrots, sweet potatoes, and even cabbage have a tremendously long "shelf life" when they are growing in the garden. Peppers will grow 2 or 3 years sometimes, remaining productive for multiple seasons. Artichokes hang on the plant for a month or more waiting to be picked. So a multi-layers, multi-succession garden is a food-bank of sorts.
So to come back to the original post, I would re-frame your thinking toward maximum production on limited space, and where there is excess, find a way to use chickens (or a pig) to absorb that food. Permies love to use the word "abundance" rather than thinking in terms of minimal output. Less isn't more . . . . more is more. Yes, one full-grown
apple tree may supply all the apples a family may need, but what's the fun in that? I'd rather have 6 varieties, all ripening in succession, all drying out there at various times in the
solar drier, and all bringing something unique to the biome.
Best of luck.