Category Archives: Woodland

Gardening or Forest Gardening?

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It seems likely that in the coming years climate change will make parts of the world increasingly uninhabitable and their lands increasingly uncultivable, leading to population movements towards the remaining cultivable areas. At the same time, energy prices will probably continue to rise, resulting in a situation where more people have to be fed from less land using fewer inputs. What would farming look like in that situation, and what kind of societies would result from it?

An army of technocrats and associated cheerleaders are hoping to engineer their way out of this troubling situation. Who knows, maybe they’ll succeed – at least temporarily. In the mean time, permaculturists and many in the alternative farming movement are focusing on more homespun small-farm solutions involving labour intensification, close resource husbandry (soil, water, energy) and the like. But of course we don’t really know if that will succeed either.

Maybe we can get some kind of inkling about the likely ecological and social shape of a future intensive small farm society by looking at examples of such societies from the past. Like colonial Indonesia, for example, as analysed by Clifford Geertz in his book Agricultural Involution: The Processes of Ecological Change in Indonesia. It’s an old book, first published in 1963, and I have to admit it’s one of those classics that I was supposed to have read in college but never did. Still, only about twenty years later I’ve put that right, and I think what Geertz says is of interest when applied to our contemporary predicaments.

Geertz contrasts two indigenous forms of Indonesian agriculture – the swidden (‘slash and burn’) agriculture of the forest and the sawah agriculture (wet rice paddy) of the cleared terraces. Swidden involves cutting and burning primary forest, and then reseeding the cleared area with a complex interplanted polyculture of annual and perennial root, leaf, seed and woody crops, using leguminous crops and the ash as fertiliser. After a few years of production, the cleared plot is left to return to secondary forest before being cleared once more after a lengthy fallow period. Swidden was often regarded as an irrational and destructive agriculture by earlier generations of western analysts, but Geertz and other anthropologists of the 1950s and 60s showed that it was subtly adapted both to the needs of the farmers and the ecology of the forest – it was “a canny imitation of the natural landscape” in which “a natural forest is transformed into a harvestable forest” while retaining the same basic form of the natural ecosystem. In other words, its logic was a lot like that of the temperate forest gardens that have been popularised by the permaculture movement.

Of course, the two aren’t identical. For example, swidden is mobile because tropical forest soils are generally poor with the majority of ecosystem nutrients being held in living biomass which has to be unlocked through burning. Mature forest trees also need felling in order to establish more manageable and useful woody crops. Forest gardens, on the other hand, can take advantage of nutrient rich soils in temperate climes and of modern dwarfing rootstocks. But both are ways of mimicking early woodland succession to preserve perennial polyculture while diverting it to human ends.

One problem with swidden mentioned by Geertz is that, despite its complexity and its preservation of ecosystem properties, what he calls its ‘equilibrium’ is a lot more delicate than that of natural forest. Managed badly, swidden easily leads to ecological deterioration, and the replacement of forest cover by invasive grasses that create ‘green deserts’. One way this occurs is through population pressure – if the fallow period is excessively shortened, or the system is otherwise overdriven to divert more of the nutrient cycle into extra human mouths then productivity decline and ecological deterioration result. In other words, the system isn’t expandable.

Not so with sawah, according to Geertz. The stability of the rice terrace as an ecosystem, he says, means that “even the most intense population pressure does not lead to a breakdown of the system on the physical side (though it may lead to extreme impoverishment on the human side)…the sawah seems virtually indestructible”. The output of the rice terraces can be “almost indefinitely increased” by what Geertz calls “careful, fine-comb cultivation techniques”, in other words by intensive gardening (horticultural) rather than agricultural techniques: pregermination, transplanting, exact spacing, careful composting, meticulous weeding and harvesting.

Perhaps we could express these contradictory tendencies of swidden and sawah in the jargon of economics. A lot of jobs can be more easily completed when there are more people to help (“many hands make light work”).  Indeed, often each extra (or ‘marginal’ in economic jargon) person contributes as much or even incrementally more to the final result – there is constant or increasing marginal productivity of labour. But there comes a point when adding yet more workers starts to have a proportionally lower effect (“too many cooks spoil the broth”) – there is diminishing marginal productivity of labour. That point of diminishing returns is reached quite quickly in the case of swidden, to the extent that adding more workers (ie. experiencing population growth) threatens the very ecological viability of the system. But with sawah marginal productivity doesn’t seem to decrease– you can achieve constant returns to labour.

It’s interesting to apply this marginal labour analysis to growing methods in drier, more temperate climates such as here in the UK. So for example forest gardens are often extolled for their abundance and designed redundancy. You’re never going to pick all their fruit, all their edible leaves and other goodies. But it doesn’t matter – it’s there for the picking if you want it, and if you don’t it’ll fill the belly of a bird or a beetle and somehow cycle its way back through the system into a future crop.

I think that makes a lot of sense given the nature of the present UK economy. Most of us don’t need to grow food for subsistence, but most of us don’t have much spare time either, so if we’re going to grow food it makes sense to opt for a low input system like a forest garden (besides its ecological advantages over other growing systems). Suppose, however, that we face the situation mentioned at the outset of rising food and energy prices and a rising local population. Growing space is now at a premium, and you have to start looking to your forest garden as a real source of subsistence. You used to harvest its best-looking apples and plums, grab a few welsh onions, snip the occasional herb, and then pretty much leave it alone. Now you go back to it, looking to reap more of its abundance. The wineberries are pretty tasty, but crikey it’s a lot of work fiddling about with all those little fruits. How many orache leaves do you need to pick for the family lunch? And where exactly has that walking onion wandered off to? I strongly suspect that, as with subsistence swidden, diminishing marginal productivity of labour will quickly kick in, and the cleverly redundant abundance that you designed into it might start to seem more redundant than abundant.

Let me be clear that this is in no way intended to be an argument against planting forest gardens, but it is an argument – or at least a hypothesis – about the returns to labour that forest gardens may furnish. Temperate forest gardening is still in its infancy, so maybe people will come up with forest garden designs with good marginal labour productivity. But only if we think about the issue – simple advocacy for abundance too easily neglects it, and this is an important omission in David Holmgren’s discussion of the ‘maximum yield fallacy’ in his influential book Permaculture: Principles & Pathways Beyond Sustainability (p.159).  For while he’s right to criticise mainstream approaches for focusing too narrowly on single yields at the expense of considering secondary yields, without considering marginal labour productivity those secondary yields can all too easily turn out to be rather theoretical. Holmgren asks us to contrast a high energy input monoculture with a low energy input polyculture to suggest the superiority of the latter. But Geertz’s analysis suggests that in situations where low energy input is a given, high labour input monocultures or near monocultures may sometimes outperform low labour input polycultures in terms of marginal labour productivity.

So would the same hold true for a future low input UK agriculture? If the forest garden doesn’t yield enough, can you bend your back a bit more in the intensive vegetable garden to make good the deficit? I suspect our temperate dry-land staple crops don’t offer the extraordinarily constant returns to labour that Geertz reports for sawah.  I haven’t yet located any useful data on marginal labour productivities (either on a per unit area basis or otherwise) – and indeed Geertz himself is a bit coy on the hard numbers when it comes to Indonesian sawah. I’d be interested to hear from anyone with some relevant figures. But in the absence of proper data, here’s a few factoids:

  • The highest reported rice yields are 5.21 times higher than global average yields, whereas the corresponding global figures for wheat and potatoes (the two key UK staple crops) are 5.03 and 5.06 (source – trusty old Wikipedia).
  •  Average UK (arable) wheat yields have increased fourfold since the 1880s as a result of technical developments such as synthetic NPK fertiliser, dwarf cultivars and fungicides, currently averaging around 7.8 tonnes per hectare (but each subsequent yield-increasing technique is likely to offer incrementally less).
  • In his excellent book Small-Scale Grain Raising Gene Logsdon reckons that a small grower in the temperate USA can grow about 6 tonnes of wheat per hectare, enigmatically adding that “a really good wheat grower with a little luck” could double that yield (apparently the world record wheat yield is 15.6 t/ha by a New Zealand farmer).
  • John Jeavons, doubtless a really good wheat grower – and one who has the luck to live in Southern California – reports wheat yields for his biointensive methods of 12.7 t/ha.

Actually, given that Jeavons’ methods are highly labour intensive, maybe a comparison of his maximum yield figures with national average yield figures might give us a handle on marginal labour productivity (though of course his methods don’t only involve applying more labour). Taking the ratio of Jeavons’ maximum productivity to average US productivity (derived from pages 143, 151 and 153 of his book How to Grow More Vegetables…8 edn) his figures are as follows:

  •  Potatoes    9.3
  • Rice             6.3
  • Wheat         4.9

So maybe rice meets its match with potatoes as the temperate staple to focus labour intensification around (though presumably his rice figures are based on dry cultivation, not paddy). Well, I hate to say I told you so, but millions of Irish peasants can’t be wrong (…or can they?) Actually, I find some of Jeavons’ figures rather curious. And few organic gardeners I know in the UK manage to match the average arable potato yields here of about 45 t/ha, which – to put it mildly – is some way below Jeavons’ maximum yield of 382 t/ha. I’ll try to come back to this topic with some better data in the future.

So where does all this lead? To be honest, I’m not entirely sure, but inasmuch as climate change and rising energy costs might force us to intensify agricultural productivity with low input methods in the future, I’d predict that in the UK we might see relatively little use of techniques like forest gardening, more use of techniques such as orchard silvo-pastoralism, more people working harder to produce smaller yield increments of staple crops (potatoes?) and a worrying convergence between actual demand and theoretical maximum supply for such crops. In other words, we might see a UK farming landscape that doesn’t look too different from the traditional small-scale mixed farming of our forebears. Which maybe shouldn’t be too surprising since indigenous agricultures have generally figured out better than anything how to feed local populations maximally in the context of energy constraint.

In the past, Europeans managed to revolutionise local food availability by various means: technical innovation, exporting people or importing food through colonial or trade relationships. I suspect that none of those options will be so easily achieved in the future, which will mean people may have to work harder for less reward to earn their bread. A big issue that this raises – and that Geertz’s study also touches on – is what society would look like in those circumstances. But that I’ll leave to the next post.

Seeing The Wood For The Trees…Again

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I posted a while back about the relative merits of grassland and woodland for food production. Here’s a little addendum to that post.

Suppose you can produce 170kg of beef from 1 hectare of grassland annually – quite a generous supposition, I think, if the cattle are being fed from the grass alone. That amounts to something like 1,960MJ of food energy.

Suppose alternatively that you have two oak trees and two crab apples on your hectare of woodland, producing something like 160kg of acorns and 100kg of crab apples annually. In practice, you’d probably have more than that, or at least you’d also have some other trees or shrubs producing something of food value, but frankly harvesting it all would be a pain so let’s take those figures as a realistic achievable harvest. That would yield something like 2,680MJ of food energy.

Now, I’m not saying that this crude exercise tells you anything very significant about whether you should choose woodland or grassland in any particular situation. And there are lots of additional factors to consider – other nutrients, processing inputs, fertility inputs and outputs, joint products, management issues, system redundancies, and palatability to name a few (a plate of roast beef or a plate of acorns – I know what I’d choose). Still, on the face of it this suggests to me that choosing to plant a woodland may not necessarily be inferior nutritionally to retaining permanent pasture, which is interesting.

In my earlier post I hedged my bets a bit, but I suppose my general drift assumed that a mature woodland was of less food value than permanent grassland. But now I’m not so sure that this is necessarily the case.  Well, that’s the beauty of a blog, I suppose. Yesterday’s thoughts disappear off the bottom of the page, and are easily replaced with today’s entirely different ones. And nobody will notice and give me any grief about it, with the possible exception of Paul Hillman. But I don’t expect he’s looking.

Seeing the wood for the trees

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I mentioned in my last post the coppice woodland at Vallis Veg – now officially ‘non-coppice woodland’ courtesy of the Rural Payments Agency, as I explained. That seems to lead naturally into a discussion of woodland at our site – or more specifically into the vexed question of the relationship between woodland, grassland and cropland – which I shall probably have to explore in more detail over time.

To start with, let me outline the different land usages on our site. When we bought the land (around 18 acres altogether) it was 100% permanent pasture. We now have about 2 acres of cropland (though some of this is down to temporary grass leys), 5 acres of permanent pasture and 10 acres of woodland. The woodland in turn breaks down into orchards (2 acres); forest garden (1 acre); ash, hornbeam and willow coppice (3 acres); and amenity woodland (4 acres).

I’ll assume that the orchards and forest garden are fairly uncontroversial forms of land use – I’ll probably post more about them in the future. What’s getting increasingly contentious these days (not that you’ll read about it in The Sun – though maybe one day you will…that’ll be when we know we really have blown it ecologically) is the balance between woodland proper, permanent grassland and cropland.

In his excellent book Meat: A Benign Extravagance, Simon Fairlie writes “There is a fringe of the green movement which has managed to reduce the complexity of nature to the formula ‘trees good, no trees bad’….If such people get hold of an area of grassland, often the first thing they want to do with it is plant trees all over it. The fact that someone, a long time ago, went to a lot of trouble to get the trees out, and that generations of people have spent energy making sure that trees stayed out, is lost on them” (p.239). In contrast to the products of the grassland a tree trunk, says Fairlie, is “a triumph of inedibility” (p.233).

Incidentally, I keep referring to Fairlie’s book on this blog, calling it ‘excellent’, and then disagreeing with it…and I’m now going to do it again. But it is excellent – the most comprehensive and nuanced case for global small-scale agriculture that I’ve come across.

Fairlie’s point is that woodland is a low value, fairly unproductive land use, whereas good agricultural land is best reserved for higher value agricultural use – particularly as we look forward to a time when we may have to make more effective use of every bit of farmland we have. The tree fetishists, on the other hand, have more nebulous – perhaps even spiritual – ends, like creating nice treescapes for human repose. Such dilettantism cuts little ice with Fairlie – “Woodland today,” he says, “is often planted according to the whims of people whose material livelihoods are more or less unrelated to the rural economy, so if these plantations meet the needs of future generations, it will be more by luck than design” (p.242).

Now, we did plant the amenity woodland at Vallis Veg with some of these vaguer aims in mind. Certainly, despite their inedible trunks, people seem to have a spiritual affinity for trees rarely felt for the annual herbaceous plants that actually feed them, with the possible exception of wheat (we had no trouble recruiting people to help us plant trees at Vallis Veg, whereas volunteers for my onion-weeding events are thinner on the ground). We also planted trees for what seemed at the time more practical objectives – future timber, privacy screening, wind protection, biodiversity, carbon sequestration. We didn’t feel able to manage livestock on the whole 18 acres, so woodland instead of grassland seemed like a good idea.

Reading Fairlie’s analysis has given me pause for thought. Support for it comes from woodland expert Oliver Rackham’s formidable (and excellent) book Woodlands. Rackham points out that woodland plantation on farmed grassland doesn’t usually add much biodiversity, mainly benefitting wildlife that’s already thriving like deer, pheasants, rooks and squirrels (oops…) And you don’t ever get a woodland ground flora if you plant on farmed grassland – you just get tussocky, weedy grass (though actually that is quite good for a lot of wildlife, though hardly very productive agriculturally). Rackham also dismisses carbon sequestration as a worthwhile objective for UK woodland plantation. “Exhorting people to plant trees to sequester carbon dioxide is like telling them to drink more water to hold down rising sea level” (p.439), he says, which is probably a fair point, and not a bad analogy inasmuch as tree-planting and water-drinking are essentially both parts of short-term cycles, whereas the real issue with carbon is our exhumation of long-sequestered reserves laid down in coal measures and oilfields.

So can a case still be made for farmed grassland wood plantations? I think so, if it’s done with proper care. For starters, I’d make the following two points:

  • because energy is currently so cheap, wood can be economically imported from almost anywhere for almost any use, including low grade ones like firewood. In the future, that’s unlikely to be the case. Demand for local firewood, craft wood and other forms of coppiced wood is likely to be high, so there’s a case for establishing local plantations – certainly not on all farmland, but possibly on some farmland. In this respect, I disagree with Fairlie’s view that people who aren’t tied to the current rural economy will make worse decisions when it comes to woodland than those who are. Rackham says “The landscape is full of trees grown for obsolete reasons, and probably always will be” (p.361). There have been times in history when coppice woodland fetched more per acre than arable land – the tree fetishists may yet prove to be right!
  • the main alternative to woodland is usually permanent pasture with grass-fed ruminants, and this is a low productivity system. With a bit of ingenuity, woodland systems may be equally productive. To make ruminant systems more productive would involve ploughing up permanent pasture and adopting grass ley/arable farming – but this has drastically negative environmental consequences, and most of the yield benefit would probably come from a one-time cash-in of the fertility accumulated in the permanent pasture.

The crux comes I think with the ‘ingenuity’ I mention that’s required to make woodland as productive as permanent pasture. Having watched my plantation ecosystem develop for a few years now, and having read Fairlie and Rackham’s thoughts on the matter, I’ve come to think that we probably do need to intervene more actively to balance some of our original goals with a greater emphasis on productivity. Here are my current three favourite ideas:

  • wood pasture: both ruminants and woodland are low productivity systems, so hey why not put them both together and graze ruminants on the grass between the trees? There are lots of practical issues to sort out here – the tendency of the animals to eat the trees rather than the grass (which probably indicates that all pasture ought really to be wood pasture), the competition between trees and grass (what Fairlie calls ‘the struggle between light and shade’) and so on. But there is a long and noble history of wood pasture in the UK, now sadly neglected in the face of intensive modern agriculture. Time perhaps to bring it back?
  • pigs, chickens and people: all edgeland creatures to a greater or lesser extent, happiest neither in deep forest nor treeless plain. So perhaps we can structure our woodland for our mutual benefit – acorns, crab apples and beech mast for the pigs (in addition to some fodder crops, of which more another time); invertebrates and perches for the chickens; birch wine, rowan jelly, acorn bread and hammocks for the people. Sounds idyllic.
  • forest gardening: this is catching on quickly, aided by publications such as Martin Crawford’s recent Creating A Forest Garden – the third and final excellent book that I need to mention in this post. But most forest garden designs are quite intensive, involving lots of fruit and nut harvesting amongst other things. Perhaps there’s also scope for lower input, more foresty forest gardens, involving…what exactly? Ah well, that’s a topic for another time.

In this post I’ve talked mostly about woodland, but really it needs to be looked at in the context of grassland and cropland as well so I’ll try to post some more on that soon. In the mean time, I’d be interested to hear other people’s thoughts on tree plantations, particularly if you’ve created a plantation yourself, so do please post your comments – I know you’re out there reading this, because I have the website stats to prove it!