Med bragende flammer. Brændingskulturens metoder i fortid og nutid.

Resumé

In Crackling Flames

A series of examples of burning in association with cultivation shows that fire was used for a variety of purposes connected with the winning of the necessities of life. Fire was used against forests of all types, from the tropical rain-forest to the coniferous and deciduous woods of the temperate zone; and the surface of the ground, with its greater or less coverage of soil, has been burnt together with the vegetation growing upon it, whether this consisted of scrub, heather moorland, grassland or peat. Fields of stubble have been burnt after the harvest. Branches and rubbish have been taken out onto the fields and burnt there, or ashes have been carted out and used as fertiliser or medicaments for the plants. And finally heathland, bramble scrub, reeds and grass steppes have been burnt off, not in order to cultivate the ground, but in order to improve the natural vegetation, to the advantage of other forms of food-winning, pasturing of sheep, gathering of edible fruits or improvement of hunting.

The methods used are just as manifold as the aims. The primary clearing of forest was normally sited on the slope of a hill with easy access to rivers or lakes. Trees were felled downhill. Sometimes the bark of the largest trunks was ringed, resulting in the trees losing their foliage and gradually dying. Or sometimes a number of trunks were cut half through, so that they could be felled all at once in the so-called "windrow-felling". Particularly in the interlaced jungles of the tropics, this method resulted in a considerable saving of labour. Normally a renewed growth of the forest was ensured by letting a few of the larger trees remain, to spread their seed over the burnt-off area. Felling was in many areas a joint task, carried out either by an entire family or an entire village, or special slash-and-burn groups might be formed for the purpose. The virgin forest belonged in the last instance to the tribe as its area. But when men had put some work into a piece of land they normally thereby obtained certain rights over it. This did not prevent the people dwelling near Siegen and Trier from distributing the land by a similar system to that described by Tacitus. On the other hand, among the Dayaks of Borneo the land continued in the possession of the man who first cultivated it.

In many parts of Europe slash-and-burn areas became permanently cultivated fields. In that case, as in Scania, the in-field might be sown with grain crops year after year, as this field received all the manure from the cattle-sheds, or it might, as in Norway, be cultivated by crop rotation. The Jutland continual cultivation of crops without intermediate fallow years, was characterized by single-field cultivation on the in-field, and may previously have been associated with slash-and-burn on the out-field. In Zealand, too, in addition to the three­year rotation there were often certain out-fields which could not tolerate such frequent sowing, and which could often lie fallow for up to twenty years. At Grøfte near Sorø it was said in 1682 of the "Brent agre" in Bænkehøjsvang that they lie fallow for 15 years and are then used for two years for buckwheat and rye. Here the name suggests an earlier burning, while the type of crop and the long period of fallow is reminiscent of the burn-cultivation system of Germany. The "Brent agre" bore moreover a growth of young beech, whereas the other fields were overgrown with bracken or heather. Sometimes there was actually a definite pro­portion between the in-field and the cleared or slash-and-burnt area, as is known from Finland, from Norway in 1490 and from the Burgundian Law of about 500 AD.

In the actual burning it was important not to burn the soil "to death", destroying all the bacteria cultures and the lower animal life. On the other hand the flames had to be kept down to the ground surface. It was a question of not allowing excessive heat. But the intensity of the action of the fire depended to a great degree on the object of the burning and on the type of soil and vegetation of the site. In France marl was burnt and in England clay, as the firing released mineral fertilising substances. Finnish sources state that it was most desirable to "kytta" on a clay subsoil. In Esthonia burning should preferably take place above good loose soil with a high humus content, but there should not be too much grass in the undergrowth. Where it was desired that the trees should shoot up quickly again, the roots _must not be destroyed (Siegen). Too severe burning would also prevent the growth of grass, and if too large an area was thoroughly burnt off the trees were prevented from sowing their seed and the wood thereby from regenerating. There was therefore a risk of the area becoming heathland. The same was true if the topsoil was burnt to death. Heavy under­growth, such as was found in the damp regions of West Europe, was difficult to clear by rotting without burning, and these regions are therefore the classical areas of écobuage. Remarkably enough burning-off often encouraged the growth of nitrogen-fixing plants, broom, alder, and the like. In Further India alder was actually planted, as the ashes from this tree were considered particularly valuable.

The sowing of the various crops was normally carried on in the tropics by means of the digging stick. But this is because in this area it was normally roots which were planted, maize or rice. On the other hand, barley, wheat, rye and oats were apparently always in recent times sown by hand (broadcast). On small plots in the Tyrol, Apulia, Sicily and Sardinia, however, women sometimes sowed wheat with the help of a digging stick. In Europe, however, the seed was either covered with soil by means of a naturally formed branch-hoe or a branch-rake, though sometimes with a harrow. But it is not actually necessary to take any action after sowing on slash-and-burnt ground, as some of the ashes are blown onto the seed, which germinate on the advent of rain. A lot of the corn is, however, eaten by birds if it is not covered, while not all the seeds are able to sprout if they lie above the burnt layer. The methods of harvesting vary with the type of crop and the sort of country. Rice is cut with a tooth sickle, while in Europe various types of corn sickle were used. There seem to be traces of a connection between the balanced sickle and the introduction of winter rye into Northern Europe. Turnips were often sown by the mouth, and the plants could either be pulled up or left for sheep to graze.

Slash-and-burning of deciduous forests appears to be traceable in Europe at least back to the Early Middle Ages, while écobuage has doubtless existed in Western Europe since Roman times. From one to three harvests could be taken and it was often permitted to fence in the area during that period. But after cultivation of the slash-and-burnt area was over it was often turned over to cattle-grazing. In cases of Egartenwirtschaft the primary object of the burning was to improve the grazing area, but in the majority of cases one or two grain harvests were first taken. It was, however, necessary not to graze the slash-and-burnt area too intensively, if it was desired to let the forest regenerate. In places both in Germany and in Further India the practice of sowing tree-seed was in use, but normally sowing was achieved by allowing a few large trees to stand.

The description here given is based first and foremost on the written records, and there has been no intention of incorporating the results of natural-historical and archeological investigations of the periods previous to the Iron Age. But it would be a natural extension to use the material here assembled to cast light on the role of burning in the development of civilisation. It has been claimed by a variety of researchers that the origin of plant-cultivation is to be sought in the gathering habits of women, who invented the idea of planting in the ground again some of the roots which they dug up with their digging sticks, in order to get them to grow and increase. It is possible that this theory is correct, but it can in any case not explain the origin of grain cultivation.

The burning off of grassland and of bramble areas may well have been known before the rise of agriculture, perhaps as early as in interglacial times. Fire was known in Palæolithic times, and one of the sources of food was the gathering by the women of everything edible which they could find, roots, grass-seed, berries, insects, birds' eggs, etc. The men fished and hunted. And the system of burning the grass off in order to attract game to the new-sprouted grass is extremely simple. In the foothills of Northeastern lraq, in the earliest agricultural culture yet known, that of Jarmo, Hans Helbæk has demonstrated the presence of a primitive type of wheat which greatly resembles the present wild wheat, triticum dicoccoides, and which is much coarser than the earliest emmer hitherto known. A few impressions of grains of another primitive type of wheat, tr. monococcum or emmer, which developed from the wild tr. aegilopoides, have also been found in Jarmo. It would appear reasonable to assume that grain cultivation arose in that area, where the highland steppes, with their wild grain species, meet the wooded parkland of the river valleys, with their abundant game. In this area methods of burning-off the land have survived right up to the present (cf. p. 76). There is no great difficulty in imagining that some of the steppe may have been burnt off in order to attract the animals of the chase. Seeds of wild wheat have then been carried by the wind into the burnt area and have there found exceptionally favourable conditions for growth. The step from wind­sowing to broadcast sowing does not appear insuperably large, and the women had thereby the open field which they needed for the cultivation of these species of corn. Covering of the seed would not, as we have seen, be strictly necessary. How early the use of harvesting knives of flint, such as are found on Mount Carmel from the Natufian Period, was discovered is unknown. But presumably in the beginning the seeds were pulled off the ears with the fingers, so that they fell into a bag or a basket. From the foothills agriculture spread down to the plains as the population grew, and here irrigation was taken into use, followed by the hoe and the plough. Agriculture thereafter spread with the Neolithic cultures, either with or without preliminary burning, along the "fertile crescent" to Syria and Egypt, and then onwards along the Mediterranean and the Atlantic seaboard to Northwestern Europe, while at the same time other similar movements followed the river routes from the Black Sea. It was perhaps first and foremost these latter which pushed their way through immeasurable leagues of forest and brought the practice of slash-and-burn to Denmark, though it appears to have, been only very shortly afterwards that the other wave of culture had arrived from the west, bringing with it the practice of grain cultivation on small plots (reiter) without preliminary burning of the vegetation as recently suggested by Troels-Smith.

This is not the place to discuss how the process developed in detail. But it must be admitted that the hypothesis here put forward concerning the origin of grain cultivation is difficult of proof, as the regions between the high lranian plateau and the river valleys of Metopotamia are not favourable to the preservation of carbon strata, the climate being too dry for peat bogs to form. Attention should, however, perhaps be given to the possibility of finding alluvial deposits, identifiable and dateable, containing carbon particles from the burning-off of the vegetation which must have preceded the first cultivation of grain.

Axel Steensberg