In permie books, etc, I often hear something like this. "Look at the forest, or look at the giant sequoias, or the Redwoods. They grew without any tilling, fertilization, or irrigation! The same method will grow great food!"

Now, I am a proponent of low or no till farming, deep mulch, etc.

However, I think the quote above embodies a big mistake. If you planted a tomato next to a sequoia, it would not grow as tall. In fact, it might not grow at all. Just because a certain soil can grow giant trees does not mean that it will grow annual ruderal plants, perennial forbs, or orchard trees. Forest ecosystems are not very good models for us. Most of our crop species are mid succession. In fact, "forest gardens" are never actually based on a forest, since they are usually full of mid succession, open woodland and shrubland species.

Rant over.

Does anybody else feel this way? I think a lot of permaculture folks get a bit too starry eyed about this sort of thing.

It might be objected that more oxygen is required in the soil than can enter the undisturbed mass. Perhaps. In that case we should study the undisturbed forest floor. The surface of the soil where the giant sequoias grow was suitable for their needs a thousand years before the mouldboard plough was invented. It is not thinkable that such giants could have developed in the absence of an optimum amount of oxygen in the soil. It must be, then, that growing plants do not require more oxygen in the soil than naturally enters it in the absence of water.

Here is the fallacy, in "Ploughman's Folly." (He is talking about the misuse of plowing aerate the soil.) "Optimum supply of oxygen" for what? Annual plants, and even some perennials, are adapted to disturbed soils, many of which contain a lot of extra air. Other plants depend on ants, burrowing animals, or other localized conditions to provide more air. Finally, some plants grow in swamps with very little if any oxygen in the soil.

He may be correct to reject the moldboard plow, but his reasoning is faulty. And not only his, but many similar authors.

I think that he wrote from his experiences in a particular place.
Acreage in the middle of farmland.
I see the same thinking in many books.

What works in New England may be a total failure in the new (and alkaline) soils of the southwest.
Each author seems to find what works best for him, in his location, and then compile a book showing the 'optimum system'. For decades, most of the big publishing houses were in New York. Consequently, most gardening books were geared to eastern gardeners.

It wasn't until the 'back-to-the-earth movement' that thousands of young folks on the west coast began seeking out little corners of California and Oregon to restart their lives. Many of the new books (especially organic) began being published on the west coast.

Many of those books are inappropriate for those in the east, just as the eastern books were not relevant for westerners.

With this new movement nearly 50 years old now, much has been discovered, both by science and anecdotal experience that many of the older books are no longer relevant. While they served during the beginning years, their time has passed.

Hello John,

I though I would clarify; I don't doubt that an untilled soil can have enough oxygen for a successful crop.

What I do object to is people pointing to sequoias to prove this. It no more proves the point then the fact of giant kelp growing in the ocean proves that tomatoes can grow there. The plants are different, the ecosystems are different, and the ideal oxygen content or soil type depends on the plant in question.

In any case, I agree with you. I don't think there is a one size fits all gardening system. Farming is one of the most location specific things there is, and we could explore and experiment in our own area for a lifetime without creating the perfect solution even for that area.

What I do object to is people pointing to sequoias to prove this.

Precisely. The Sequoias (just like the giant California Redwoods) have found their niche in a climate/ecosystem that suits their needs. You won't find them in the Sonoran Desert. A planting of Prickly Pear Cacti would probably not do well where the Sequoias prosper.

Folks espousing the forest garden, such as Martin Crawford, seem to me to make it obvious they are talking about a young forest, not a mature forest of Sequoias.

Temperate food forests are constantly in flux with a mixture of tall and short plants. Seems like a meadow to me.