The paper looks at breadfruit, air potato, carob, chestnut, Enset, banana/plantain, sago palm, evergreen oak/encina, yeheb nut, Mayan breadnut, perennial beans, almonds, nuts, olives, coconuts, avocado, honey locust pods, and tahitian chestnut and their potential to replace part of the dependency on cereals.

It would be great if we could get more of our food from trees. It would reduce labour input and pesticide input.

You can also multitask the land better often with trees. My grandfather used to have cattle among breadfruit trees on his farm. Breadfruit is great stuff, lots of uses.

This article makes me want to take a closer look at Brazil nuts. Figure 3 shows a yield close to 5 t/ha and being nuts they are more nutritionally dense than boring starches. (There's a lecture series you can find on youtube called something like 'nuts as a staple food')

Then around Figure 4 they talk about how trees growing perennials would lock up more carbon than cropland.