Traditional farming in the rainforest

If an acre of rainforest can’t support a single orang-utan, what chance do humans have of living without traditional farming?

Sorry, but it’s no good. I don’t get permaculture. And the more I read, the less I get it. According to an article in the RHS magazine The Garden, permaculture is “a state of mind or a way of thinking”, and involves “using the energies of the environment, rather than fighting them”.

So far, so meaningless. What actually is it? Examples of permaculture mentioned in the article include growing ornamentals and edible plants together, composting, collecting rainwater and buffering your greenhouse against extreme temperatures by putting a few large containers of water in it. These are all well and good, but surely just examples of ordinary good gardening?

On the website of the Permaculture Association, I quickly learn that permaculture will make the world a better place (and me a better person, likely as not), but still nothing about what it is. Back to The Garden, which tells me that a primary feature of many permaculture gardens is the “forest garden”, and that I can learn about that from the Agroforestry Research Trust in Devon. From their website I learn that agroforestry is an agronomic system based on trees, shrubs and perennial plants, which fits with the derivation of “permaculture” from “permanent agriculture”, i.e. gardening based on not digging things up.

Now we’re getting somewhere, but before we go any further, some essential background. At a global scale, the pattern of plant productivity depends on temperature and water, so a world map of productivity reflects that; productive where it’s warm and wet, unproductive where it’s cold and/or dry. At a smaller scale, soil fertility is crucial: plants grow fast on deep and fertile soils, but slowly on shallow, infertile soils.

So throughout history, farmers (or anyone trying to grow food) have done two things. First, they’ve tried to alleviate whatever is limiting local productivity, usually by irrigation or adding fertilisers. But raw productivity itself is little use. If the seedlings I keep pulling up are any guide, if I left my veg plot for a few years it would quickly become an ash wood with an understorey of holly and yew. Certainly very productive in terms of biomass per annum, but not particularly edible — at least not by me. Even if I could live on ash keys and holly berries, I think the novelty would wear off pretty quickly.

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