by mos6507 » Thu 11 Nov 2010, 21:25:35
The problem with permaculture, which I agree with SixStrings on, is that it does not operate at a human timescale. It has a slow ramp-up speed on its theoretical yields. A multi-level food forest with a canopy species like chestnuts is a multi-decade investment towards maturity. Over the same timescale I'm sure you could grow far more calories in annuals.
If permaculture had swept the world 30 years ago, we'd be in pretty good shape today. But a crash program today will fall short because it won't reach maturity before TSHTF. And with each year that passes, the ability of permaculture to soften the blow of collapse recedes.
That doesn't mean it isn't still useful, but like SixStrings says, when people panic, and they have limited land to work with, they will not be planting chestnut trees. They will plant survival gardens with potatoes and beans into their marginal topsoil and just hope for the best.
There is a lot of dispute over permaculture yields. I have the "A Forest Garden Year" video from Martin Crawford. In that he says point-blank that yields per acre don't match traditional agriculture. This is someone who has put 15 years into his plot. Geoff Lawton, on the other hand, has made some outlandish claims about how many people you can "feed" per acre. So it's hard to know exactly where the truth lies.
A big part of the problem is that perennial systems don't map to the human diet as nicely as annuals do. It's easy to have some fruit trees, and have more fruit on hand than you could possibly eat, but that's not a balanced diet. So simply counting calories is not the way to measure "yield". You have to look at how well a polyculture system can approximate a functional diet, otherwise people will continue to lean on traditional systems for the things they aren't getting from the food forest.
Take someone like Robert Hart. He was a raw food advocate, and a vegetarian. Within his (relatively small) food forest, he pretty much covered his household fruits and vegetables. But he still had to buy grain.
Worst of all, perennial systems require that you stay put, or that you at least pass the torch to new owners who will continue where you left off. Annual agriculture is like pitching a tent and perennial polyculture is like building the pyramids.
Robert Hart's food forest is now in a state of decay thanks to the apathy of the new owners.
And I've put a lot of time and money into edible landscaping here, and odds are when this house is sold, it will all be scrapped. Whatever dividends were earned through several years of grapes, blueberries, gooseberries, currants, raspberries, hazelnuts, etc... will be wiped out in order to put up yet another McMansion. However, as long as you've got good soil and some seeds you can start right up again wherever you go.
This to me is why annual agriculture has become so dominant. Human culture is too transient and destructive for a lot of perennials to make it. Greer mentions something along these lines in The Long Descent. Did annuals make us that way, as Ishmael suggests, or is it merely a reflection of how we wanted to be anyway? Kind of academic to think about the chicken and the egg when you've got 6.9 going on 9 billion people to feed.
This is also the intersection point between permaculture as an alternative form of agriculture, and as more of a social movement. Permaculture systems really call out for people to stay rooted, and to think in terms of ecosystems rather than nice little square fields. People themselves being PART of the ecosystem (zone 0 if you will). For instance, my backyard is a hill. Ecologically, the entire hill is like one system that could be redone in swales and all that stuff. But since I'm in only 1/4 of it, I can only work on my segment. This has a lot of drawbacks. Trees need pollinators, and sun exposure, etc... At a suburban scale, collaboration with neighboring plots would significantly increase the potential of what could be done. So permaculture could help break down borders, if people were to change how they think about land-use.
You've got to decide what your objectives are. Is your objective to kick the can down the road? If so, then why not keep the green revolution going? Use all that shale gas to make nitrogen fertilizer. Then coal. Then nuclear (all you need is electricity for haber-bosch). There are plenty of ways to stack a few more cards on the house of cards. What permaculture does is try to envision a positive end-game, something that could call a truce between mankind and the biosphere without dying back all the way to Georgia Guidestones levels.
And considering that permaculture has the potential to restore degraded ecosystems, it's also important for the few of us who give a damn about biodiversity as well as human carrying capacity. Adding yet another wheat field to the world will only increase the population of rodents and UG99.
So try to think a little deeper about these issues rather than jumping to sound-bite rebuttals.
If you want to grow really a lot of those things, I suggest Biointensive, which is a very simple system but one which to my way of thinking is too much work. But boy howdy can it grow a lot of potatoes! 
I will be raising chickens for eggs and meat. But probably not producing all of my meat on my own place - I've contracted with my sister to get rabbit meat from her. I used to be mostly vegetarian but have recently become convinced that's not necessarily the most healthy diet. So far I have lost weight on the paleo diet which is important because I have congenital high blood pressure and anything I can do to keep it down is beneficial.