European Regional Smog from Peat-Swamp Burning in Germany
(IFFN No. 18 – January 1998, p. 59-60)
Historic Moor Cultivation
In the 18th century the landscape of Northern Germany was dominated by large uncultivated bogs and swamps. In 1770 about 1/7 of the total area of Niedersachsen was uncultivated bogs. The common people were afraid of these ‘dark and wild’ places and tried to stay away from these areas, which were perceived to be haunted. But with the population growth of the end of the 18th century, people were forced to enlarge the area under production and started to cultivate these areas. To fulfill their plans they began to burn the bogs.
The chosen plots for the new settlement must first be drained and levelled of. This work was done in autumn with the establishment of ditches which were laid out in such a way that the plot was divided into long narrow strips. The purpose of this work was to dry out the plot for further treatment. In spring of the following year, the upper organic layer of the bog was removed with big hoes, and the duff was cut out in quadratic clods. If the year was very wet this work was done in early autumn. In these wet years the ground had to be broken up several times.
In May work requiring strong men began: the clods had to be thrown and stacked into little piles. Thereafter these piles of stacked and dried clods were ignited. As soon as the material was half-burned, the still burning pieces were distributed against the wind all over the field. The fire had to burn for several days at calm weather for several days. It was very important that the fire be watched over so that it did not penetrate the deeper organic layers. The bog area only had to burn slightly or, in other words, smoulder. This work was extremely strenuous and the workers’ clothes were covered with ash and dust, while their eyes were constantly a shade of red during the burns.
The burning of the bog began mainly in mid-May and ended in June. The drying of the organic material and the heat caused the normally barely accessible plant nutrients of the bog to break up enabling the cultivation of oat and buckwheat on the freshly burned fields, without fertilization.
The burning of the bogs was however not possible on the same plot year after year, over a longer period of time. In general a single plot was burned and tilled over a period of six to seven years. After the cultivation period a fallow period of 20 years was necessary. For this reason shifting cultivation was practised, where thereafter a neighbouring plot was used for the next 6 to 7 years, after which new land was then cultivated.
The burning of bogs was first noted in the year 1583. At that time the regional administrator (Drost) of the Emsland enacted a strict ordinance against this kind of “cultivation”.
In 1669 similar ordinances existed in the counties of Oldenburg and Delmenhorst. In 1720 the following was written: “In the Emsland the farmers are not willing to desist burning the bogs. They rather would pay the fine and continue to burn.”
The first stimulus for the agricultural use of the moor came from the Netherlands. The upper organic layer of the moor was used for peat production and afterwards the dismantled moor was cultivated (“Fehn” cultivation).
Burning practices were introduced as well from the Netherlands to Eastern Friesland and spread from there throughout northwest German bog areas.
The “Dry Fog”
The burning of the bogs had an oppressive effect on the northwest German areas, even in areas far away. This effect, the “smell of burning” was known under the term “High Smoke”. What is “High Smoke”? Why was the smoke of the bogs called “High Smoke”?
The bog researcher Racke wrote: “The dark, thick and heavy, evil-smelling smoke covered the land for miles. In the spring often in the shape of a high dark wall, it rapidly gathers like a storm-cloud and covers the sun so that it looks like a dim disc. At more favourable conditions the smoke escapes, and the longer it travels the weaker it gets, ending as haze, carried into areas far away as Hungary or Southern France. In Germany this phenomenon is called “Heerauch”, “Haarrauch”, “Höhenrauch” and is hardly liked. Public opinion made it responsible for all sorts of damage. It is said that it drives away rain. The farmers of the “Alte Land” said that it damages the blossoms of fruit trees, and that it should even drive melancholical people to suicide.” For years the inhabitants of countries far away from the actual bog burns were puzzled over the origin of the recurring smoke. The French, for example, thought that the “brouillard sec” was dried fog. The English called the bogsmoke “dry fog”. The puzzlement did not stop:
In 1657 the bog burnings began on 6 May in Northern Friesland carried by strong easterly winds. Already on the next day the smoke had reached Utrecht, and a little bit later had changed direction, passing Leeuwarden towards Den Helder reaching the sea on 15 May. There, the wind changed suddenly northwest and drove the bog smoke back, so that on 16 May it had reached Utrecht and Nijmwegen again. At the same time the smoke was also noticed in Hannover, Münster, Köln, Bonn, and Frankfurt. On 17 May the smoke reached Vienna, on the 18th May Dresden and Krakau on 19 May.