Tuesday, November 26, 2013

The Plantation of the Atlantic, XX: A Crisis of Growth?

So, today, because I did not realise that I had missed the 75th anniversary of the foundation of 100 Group RAF last Saturday (looks like your card is going to be about a month late. I blame Canada Post) during my enormously restful vacation, we will be talking about Alex's challenge.* Why did things get better after Rome fell?

"So perhaps you've got a Marxist explanation here: the social relations of production, i.e. the Roman political economy, are holding back the material relations of production, i.e. the productive potential of the Roman periphery, by forcing it to produce grain inefficiently to serve the interests of the elite, when it could be doing something more like classic British mixed farming or just a shit load of livestock. As a dialectical materialist, the Marxist would say that the material forces of technology always prevail in the end. And then a revolution happens. This is basically a Latin American dependencia historian's view.

There's a passage somewhere, about how in the summer the young folk of the village would go up to the high places, the boys to shepherd the cattle, the girls to milk them and make the cheese (gender essentialism!), about how the milkmaids would have skin like the Milky Way, and that they  would lie out under the stars on a summer night, their elders a thousand feet below.

...As it turns out, "sexy milkmaid" is not a very useful Google search.

Anyway, Heidi Klum, everybody. (Important safety note: Do not wear open-toes around cows.) Also, The Silencers.

There's a passage somewhere, about how in the summer the young folk of the village would go up to the high places, the boys to shepherd the cattle, the girls to milk them and make the cheese (gender essentialism!), about how the milkmaids would have skin like the Milky Way, and that they  would lie out under the stars on a summer night, their elders a thousand feet below.

...As it turns out, "sexy milkmaid" is not a very useful Google search.

Anyway, Heidi Klum, everybody. (Important safety note: Do not wear open-toes around cows.) Also, The Silencers.

I call this an investigation, by the way, because I want to hang a great, big epistemic caution on it. A blog post is not the place for a turgid, thesis-style "historiography and methods" chapter, but this is a subject that calls forth grand explanatory structures that float well clear of the facts.

So here is what we have: a 2008 study by Nikola Koepke and Jeorg Baten of Tubingen history of changing human stature that says that people got dramatically taller beginning around 400, with the trend peaking in the early 600s. It is usually a good idea to kick the tires when economic history rolls new wheels around. An enthusiasm for new datasets can sometimes lead a rather rosy evaluation of their quality. Stature estimates have been used to make claims about living conditions for much longer than we have actually had good science about stature.

 Even today, forensic anthropology still has a great deal to learn about the correlation of human stature, and the quality of forensic work is . . .uneven. I have turned up an educational site that tells students to calculate the height of a human being by multiplying the length of their femur bone by 0.31 in order to use this data point as an exercise in plotting a line. ("M" equals x multiplied by a, added to b, folks!) This site will go unlinked. On the other hand, the latest number of Anthroplogy has Agnihotri and Soodeen-Lalloo reminding us that it is still difficult to estimate the stature of living humans from fragmentary bone remains due to ethnic, dietary and climactic effects amongst others.

This caution is well-directed right now, with Jared Diamond's latest attracting attention. Approximately the millionth attempt to prove that hunter-gatherers were healthier than early farmers, it is also the latest to use Boas's Nineteenth Century finding that Sioux were taller than Hopi to prove that hunting was a healthier lifestyle than farming. (Unless it was in the Arctic.) And, once again, I want to yell: NEVER MIND WHAT YOUR INTUITION TELLS YOU, WAIT TILL YOU HAVE GOOD DATA TO DO SCIENCE. The Nineteenth Century is not the same as the 10th Millennium. Yes, it will be a very long time before we have a sufficiently robust dataset to do this study. Yes, we will have to wait until then to do the study. You are not allowed to just hook up with some data and proceed. But remember that what you are giving up in embracing the scientific method is only the ability to tell stories about now based on what might well be fairy stories, and that's not such a big loss.

Koepke and Baten, however, are not Boas. They have done a meta-analysis of published, dated, human remains from numerous archaeological digs. Europe being very well dug over, they have a pretty big dataset. (By some definitions of the word "many.") They have found 9477 individual heights reported, albet including only 2974 disaggregated individual height samples. This still doesn't strike me as enough, given the length of time and number of regions to be covered, and I still have my usual concerns. Koepke and Baten are still subject to the usual criticisms: they try out a "Roman public health" statistic, ponder the impact of the Black Death and throw the Medieval Climate Optimum and Little Ice Age into the mix. All we're missing are the plagues of Marcus Aurelius and Justinian,the Dunkirk and Mediterranean Marine Transgressions and the Great Deforestation Crisis That The Romans Did. (I assume that it has a fancy name that's cool to say, like "Transgression," but can't be bothered to look it up.) Besides that, there is the obvious forensic concern. Taking data collected over many years pushes some of it back into the era when forensic anthropologists were using poor height-estimation methods, besides issues over dating. (Even Carbon-14 dating methods have advanced significantly, while the gap between good and bad practice in Carbon-14 methods remains significant.)

With metadata, I take it that the risk is that the urge to add hypotheses to the model outruns the strength of the data set. That being said, this ought to be discoverable through statistical methods. These results should be accepted, at least until such time as statistical analysis, rather than cavilling, is the answer. (On the other hand, I still think that cavilling is a perfectly appropriate response to the data purporting to prove a reduction in height with the adoption of agriculture. Whatever your intuition might be, the dispositive data does not exist.)

So what happened? Systemic dietary deficiency is proposed. I find this unconvincing. Seasonality plays an important role in premodern food scarcity. If food is scarce in good times, it will be nonexistent in bad times. Intertemporality is key here. Food consumption must be deferred so that there will be food in the winter. But if you're hungry now, you do not store food until later. 

Now, it is not clear that seasonal food scarcity and even starvation, a fact of premodern times, must lead to lower average stature. It would be very hard to account for discovered regional differences in stature in terms of seasonal scarcity unless we want to argue that Iron Age Danes were less likely to be short of food in the last weeks of winter and the first weeks of spring than the people of Lazio. If we do want to argue this, then the issue is intertemporality: storage and, by extension, income, not agricultural method. Nor is it clear that brief periods of starvation will lead to shorter stature. How much lost genetically (or epigenetically) determined stature gain is made up in adolescent "growth spurts."These are known to be delayed, not aborted, by periods of poor nutrition. Robin Fleming seems to me to go too far in criticising naive interpretation of skeletal datasets by pushing delayed adolescent growth spurts into the 20s (the last moment before long bones close and bring all stature gain to an end), but he is certainly right to point us to the experience of seeing new conscript classes undergoing "delayed" growth thanks to army chow.

It seems reasonable to infer that Roman unfree agricultural labourers had a low standard of living and a compromised health. So, apparently, did pretty much everybody. Then, they and everybody else saw a rapid recovery. So far I have proposed intertemporality (storage or food preservation technology) and standard of living (more food to store) as issues. I leave disease aside as a special case of the question of to what degree transient episodes will affect statures already determined by heredity, class, climate and nutrition. I also find that this is a bit of a bog. (Here's a paper, published in Human Biology,that shows the average height of recruits to a British regiment in the 1700s fell in peace time and then rose in wartime (this is what a labour shortage looks like, if anyone's interested). And then, at least per the  abstract, goes on to conclude that the lower average height of recruits in the 1768--1774 cohort vice the 1775--81 is due to adverse climate events that, given the state of our historical meterological information, must be largely inferred from studies such as this.)

At this point, it is interesting to pursue the idea of reduced intertemporality/higher standard of living. Chris Wickham's preferred model for the radical simplication of sub-Roman British society starts with the end of money imports to pay the army. Without circulating money, market exchange comes to a halt. Without money, villa-owners stop paying taxes. (We cannot say that the concomitant end of taxation frees up resources, because cash money tax renders are precisely not a resource!)  

At this point, we have a set of competing theories that might explain the resulting social composition of east-and-south-of-the-70" precipitation/annually-isobar England. The classic one is that the people of Britain offer hospitalitas to Saxon foederati/auxiliaries for military secruity, and that these then revolt and conquer and settle the land. As with other stories of Dark Age social transformations/migations, the absence of any large social structures precisely at the time that this occurs suggests that this is at best a partial explanation, at worst an ideological fabrication, the difference coming down to the question of how many migrating Saxons one needs to cause national English ethnogenesis --with now in the mix the radical thesis that Nick Higham throws out without even bothering to name its adherents that the lowland British vulgate was already switching towards the Germanic during or even before Roman times. 

The second thesis sees a highly sociall-decentered or levelled society at the time of this transition, relying on the notoriousTribal Hidage  as dispositive. This is your anarcho-syndicalist (but not really!) model of the sub-Roman British Dark Ages. Notice that the power of this model depends heavily on timing. If the light goes out in 431, when the Gallic Chronicles have Britain largely overrun by Saxons, and comes on again when Saint Augustine sets foot on England's pastures green in 595, then we have a very long time in which ethnogenesis and, incidentally, stature gain can take place. If we want to push Bede, with his "everything's under control" message into the lost Brythonic kingdoms of  the Old North, as late as the 550s, and bring Augustine into a Kentish court already prepared for his arrival, than our Dark Ages become very short indeed, and we have sharp questions  indeed to press to the Venerable Bede, whose real concern might be a squalid as undercutting the prestige of the see of York. This model is of some standing, but stands contested. Did the Brigantes civitates give its name to a Bryneich that became Berenicia? Make this argument and it is beginning to look as though you are trying to get rid of all of those Grubenhaus-bearing Saxons, presumably fleeing Dunkirk III Marine Transgression. (Yet another of the great exogenous historical drivers that quite possibly never happened.)

So let's step back, because it is productive of conclusions about intertemporality, to Wickham's anarcho-syndicalist commune model, the one that's now all the rage thanks to Scott and The Art of Not Being Governed. Given that the small "subkingdoms/tribes/peoples" of the Hidage are too small to be kingdoms and too large to be estates, and that there is some continuity with the old lowland villas, Wickham proposes  a prehistory in which villa owners become the leaders of local political communities, giving up rents as patronage to buy loyalty. More surplus means more food in bad times. Higher living standards are key here, and Koepke and Baten then leap to the Reverend Malthus's defence by suggesting a link to lower population density because, apart from the whole density-promotes-disease thing, we have the implicit argument (which actually does not hold) that lower density means more land per person and thus a higher marginal return per person. 

In general this position holds water for those who want a substantial fall of population at the end of the Roman period. I have suggested before that this greatly overestimates the elasticity of human demographics, but now will wave in the direction of pollen studies, which Higham characterises as the most scientifically robust of the new historical data sets. From pollen studies in England, we can conclude that there was no significant change in vegetative cover in Britain in sub-Roman times, except in the upland wet country, where the formerly locally-self-sufficient Roman garrisons might have encouraged a bias towards arable farming in unsuitable areas. In default of the classic model of spreading forests, we need people to keep them down. No population collapse, in other words. 

So now what? Does a dramatic reduction in inequality happen on its own? Marx bad, Bakhunin good? Or do we have a technological change? My tentative answer is that the need for more horses for military purposes can be seen to drive a change. It does not necessarily mean that more horses are produced in even the medium, never mind the long term. All the evidence is that very long term waves of change are only beginning to wash over the sub-Roman countryside. The alps are not cleared over night, the fishing plantations take centuries to reach Newfoundland, the trans-Saharan caravan routes are developed incrementally, not overnight. Volubilis is not abandoned in favour of Fez until perhaps the 10th Century. Minting begins in England in the mid-600s with gold and then silver issues, in line with the expansion of the emporia, trading towns open to the sea and the emergence of kingdoms at the Heptarchic level. Then the emporia are abandoned. The trading centre outside London's Roman walls is established in the 600s, flourishes in the 700s, and then moves inside the old walls in the 800s. Why a four century delay? Why, if it is lack of money that dissolves Roman British society, do people wait two centuries to mint it? Especially given that the "barbaric radiates" tell us that people were wiling to mint money in Roman times?

We come back to the question of what happened specifically in the 400s. A political crisis of growth? 

Growth. We come back to stature. I didn't even live at the height of the age of the School Milk Programme, and this is my first intuition. As it turns out, it is that of Koepke and Baten, as well. Continuous access to liquid milk leads to growing bodies missing far fewer opportunities to, well, grow. So the intuition is good. 

Unfortunately, graphing beef bone finds versus pork does not tell us what we need to know about childhood access to liquid milk, because the main source of pediatric milk in close-to-margin societies is the goat, not the cow --you have to feed them less to get milk in the winter!--  and ovicaprine remains do not follow the inverse relationship with pork remains here required.

So a horse-related hypothesis? It goes like this: Julian throws away the exercitum Gallum. Now the Roman emperors cavalry and has no idea where to get it. So, like much more recent (Holy) Roman Emperors, they turn to military contractors to solve the problem. Under the structure of the Roman tax law, people who call themselves barbarian kings and who command armies of auxiliaries are best suited to be military contractors. They are rewarded, as Wallenstein was rewarded with the Duchy of Friedland, with tax revenues of given areas. Their armies go into quarter, the provinces produce their allotted revenues in some forms, and the model---

Well, the model fails. In the crisis of the 410s, with Stilicho bent on imposing his grandson on Istanbul as new emperor, with an usurper in Spain and then Britain, with an army coming all the way down from Britain to Austria, presumably following the classic droving paths, armies basically come and go. At the end of it, there are regiments out in Spain, others undergoing ethnogenesis in Pannonia, and no regiments at all in the rainfed pastures of upland Britain. Perhaps not coincidentally, the historically most  dangerous of the dissassembled armies presently being hosted in Spain is the one in the remote and rainy northwest. 

The problem? A contractor does not conjure with horses in the abstract. He has an actual horse (or, rather, several thousands of them.) They are lame, off their feed, or simply too worn out to go on. He might not send out his soldiers to be quartered on the land, there to make their transition from billeted fighting men to proto-feudal landlords by processes of opaque violence and co-option. 

But the horses are not going to be happy feasting in their king-colonel's mead hall. That's not how horses work. They need to go out on paddocks. One horse equals an acre-and-a-half of pasture, at least in Surrey. Unfortunately, horses are not by preference intensive grazers.  They are ranging, finicky eaters. This is why the classic pastoral advice is to graze horses alongside ovicaprines, or, more especially, goats. 

"As we investigate species behaviors, horses have a preferred grazing height of 2-4 inches. Their upper and lower incisors permit closer grazing. Treading and hoof action may also damage forages. These factors contribute to overgrazing, poor pasture quality and weed growth. Efficient grazing heights for sheep are 2-6 inches. This demonstrates the need for managing forage stubble residues to prevent overgrazing. Cattle on the other hand prefer a taller sward of 4-10 inches tall to increase their bite efficiency. Goats have a narrower muzzle than sheep with a split upper lip which adapts them for selecting plant parts. They are top down grazers preferring tall feeds and seed heads. They prefer browsing over grazing and rough and steep land. Goats can be considered renovators and be useful to control certain weeds and unwanted vegetation. They can return a mature pasture to a vegetative, higher quality stage of production. Does this mean that cattle and goats will not overgraze? Certainly not! Managed grazing needs the watchful eye of the pasture manager and 3-4 inch minimum of pasture residue remaining when animals leave a paddock. Paddock size should be small enough for uniform grazing by the animals in the paddock within a give grazing interval.
Different forage preferences show sheep consuming many weeds or forbes even when other high quality forages are available. Goats prefer brush or browse plants including brambles, mulberry, honeysuckle and multi-fora rose for example. Cattle prefer more coarse, longer forage compared with sheep. Horses and cattle tend to have considerable un-grazed material near dung piles and urine spots. Sheep or goats will graze much of this material.
Mixed species grazing can often improve pasture utilization, productivity and control problem weeds and brush without the need for chemicals. This practice takes advantage of different grazing habits and species forage preferences. Reduced parasite loads can occur with mixed species grazing or alternating species in a grazing program. Some predator control may be achieved from larger animals protecting the smaller ruminants. Economic returns can be greater from more pounds of livestock produced per acre.
Generally in a good pasture system 6-8 goats consume as much as 1 cow or 5-6 sheep. Heavy brush-browse systems will support 9-11 goats; 6-7 sheep or a cow. With mixed species grazing 1 or 2 goats or sheep could be added per cow grazing to improve pasture utilization. This uses the different feeding habits to manage pasture and optimize animal production."

I am not saying that by trying to farm out horses, the central authorities of the 400s created an arcadian utopia of correctly New Age mixed-grazing norms. I am just saying that, if you board out army horses to farmers and pay them for their pasture, do not be surprised that, lacking a strong centralised control, in practice the land that you pay to produce horses will not be turning out more profitable animals instead. This might even be construed as a paradoxical return on attempts to feudalise armies: you farm out your horses, especially where horses are dramatically unprofitable, and get pigs, sheep and cattle back.  Feudal cavalry works where horses work. Elsewhere, it is just a waste of a sipahi worth of tax farm, and our ideal warrior knight is going to end up parlaying his horse's room-and-board into a snug little estate. With no war horses. 

So, too bad about your mobilisation order, boss. I could sent my son, though, with a complete war harness and an oxcart loaded with enough stuff to buy a horse? Would that be good enough?  

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