Excursion Stop 1

Edited by Steffen Wolters Dirk Enters

08:30 Departure in Wilhelmshaven 09:15 Neuenburger Urwald 11:00 East Frisian Central Bog / Stapeler Moor 12:30-13:30 Lunch break (Urwaldhof Neuenburg) upon request the bus stops at Varel train station (departure of train to Bremen via Oldenburg 14:02, reaching Bremen central station 15:05) 14:00 Sehestedter Moor / Jade Bay 16:00 Wurt Sillens 17:45 Departure of ferry Eckwarderhörne – Wilhelmshaven, arrival 18:30 Participants have the option to return by bus to Wilhelmshaven (arrival 19:00) (possible stop at Varel train station with departure of train to Bremen via Oldenburg 19:02, reaching Bremen 20:41)

Detailed Map of the Jade Bay. The four excursion stops are indicated.

2 INTRODUCTION

Main landscape units in the coastal region Karl-Ernst Behre

Though the North German Lowlands are flat divide the freshwater-influenced areas on the and have a rather uniform appearance over landward side from the salt marshes wide areas, there are subtle but significant seasides. The present day sharp demarcation and, at times, pronounced differences in of these two systems is, of course, artificial. landscape due to differences in the history of During transgression phases the Clay its various component parts. Furthermore, if District was a tidal flat, a feature still to be one examines the cultural landscape more seen today in the vast area of the Wadden closely, it becomes evident that its different Sea where it occupies a wide strip in front of forms have developed as a consequence of the salt marshes and below the mean high and in response to the natural character of water level. About 8 km north of the coast the various components. there is a string of islands – Ostfriesische The sandy old moraine landscape, called Inseln – which also belongs to the dynamic Geest in NW Germany, represents the oldest system of the North Sea coast. These islands part of the coastal region. West of the river are a continuation of the Dutch coastal Weser a broad ridge, the Oldenburgisch- barriers and are covered by dunes. They Ostfriesische Höhenrücken, stretches from therefore look rather strange in contrast to south-east to north-west and forms the back- the tidal flats which they shelter. These dune bone of this region, sloping to the north, east islands have excellent beaches which are and west beneath younger sediments. very popular in summer. Between the rivers Weser and Elbe there are The final major landscape type consists of smaller ridges, mainly former end moraines raised bogs, which in former times covered and Geest-plates, subdivided by small rivers extensive areas of the Geest or Pleistocene and creeks. There are only two places where ground. This landscape unit has been more the Geest reaches the coastline: at Dangast profoundly changed than the others in mod- in the southernmost part of the Jade Bay and ern times as a result of peat cutting and at Duhnen, close to Cuxhaven. Both areas cultivation. Only a few small fragments have today have well-known beaches. been protected as nature reserves. The second great landscape unit is the Clay The character of the vegetation and land use District – Marsch – deposited along the in much of the region are determined by the coast and the rivers during the Holocene. acidic sandy soils of the old moraine land- Even if it is not easy to recognize, the Clay scape and by the low nutrient soils of the District has also a characteristic relief that is former raised bogs areas. Only parts of the very important for the vegetation as well as Clay District, mainly the younger Clay for the pattern of habitation and land use. deposits, have fertile soils and are excellent Nowadays, the Clay District is protected agrarian areas. against floodings by dikes; these sharply

Main landscape units of northwestern Germany

Schematic illustration of deposition and occupation in the German Clay District (Marsch)

4 EXCURSION STOP 1

The Neuenburger Urwald – an outstanding historic woodland in Lower Saxony Karl-Ernst Behre

During Medieval and early Modern Times woodland that has been utilized and trans- almost the entire Pleistocene region in NW formed by man for many centuries. Germany was covered with heaths; only in In addition to this old wood large parts of very small areas woodland existed then. One the former heathland around have been of these places was the Neuenburger Urwald afforested within the last 150 years, mainly west of Varel, which nowadays is of course with conifers, which are introduced. no primeval forest as the name suggests, but

Last impression of the former grazed forest

The Neuenburger Urwald is situated on the repopulation in the Early Middle Ages relatively good soils: Lauenburg clay of Late there existed several settlements in this area Elsterian origin is covered by a thin layer of and their fields, manured with plaggen, Saalian (Drenthe) till. There are no pollen could be traced in the wood. diagrams from the forest area, but the recent “natural” development shows the climax vegetation or at least the potential natural vegetation of nowadays. It comprises mainly three forest communities: oak-hornbeam- forest (Stellario-Carpinetum), beech-oak- forest (Fago-Quercetum) and wood millet- beech-forest (Milio-Fagetum). This forest has been used in many ways since the Middle Ages and there are many Soil map of the Neuenburger Urwald. White: sandy written and other sources about this. After soils; yellow: loamy soils, green: old fields.

5 As a consequence of the Black Death in the During the Danish period of Oldenburg 14th century, these fields as well as some (1667-1773) the forest was severely ex- settlements were abandoned and the count of ploited and several farmers from the Oldenburg took possession of the area which neighbourhood acquired small private plots became wooded more or less naturally. in the forest as pastures, the boundaries of However, the farmers around maintained the which can still be seen as slight banks and rights of forest grazing. ditches in the Urwald. During the early Modern period the shortage of timber increased considerably, mainly due to ship building and the demands of the treeless Clay District to the north. Therefore Anton Günther, the famous count of Olden- burg, initiated in the 17th century a large scale afforestation of this area with almost exclusively common oak (Quercus robur) because of its high prices. So this was by no means natural woodland but a timber forest, grazed by cattle. Boundary of an old private plot

Detail of the first map of the Neuenburger Urwald from 1782 After this period a complete reconstruction beech and hornbeam. Often two or more of the forest took place. In this connection a seedlings were planted together in one hole precise forest map was produced 1782, in order to have at least one tree that grows probably one of the oldest of this kind in up. However, in many cases two or even northern Germany. Now new plantations more developed, forming twins or even were made in the large clear cut areas, how- bunch trees, which are still now frequent in ever, not only with oak but now also with the Urwald (see plate 1).

Map by LECOQ, showing the few forests at 1805

From this time the Urwald has been used not Forest grazing around 1870 (J. PRELLER) only for timber but for many other purposes. Many written sources tell us that the humic soil surface was removed to manure the fields, the litter was used for the cattle and pollarding as well as lopping were practised, too. But the most important factor that trans- formed the wood into a semi-open area was forest grazing. The farmers around the forests owned grazing privileges and a very sophisticated system was practised to answer the various demands of exploitation. According to a chronicle of 1792, 284 horses, 861 heads of cattle, 660 pigs and 1292 geese were driven into this forest. Before this also goats had been allowed. Numerous oaks were protected as mast trees, but everything else – sprouting trees and shrubs as well as herbs were eaten by the domestic animals, which caused high pres- sure upon this ecosystem. Thus a park-like open forest, dominated by oaks, with a green floor mainly of grasses developed, which is documented in several paintings from the 19th century. From 1850 the government tried to ban forest grazing but with little Oak, capped in order to get a wider crown for success, so the wood pasture continued up to more mast the 1920ies.

7 Plate 1

Shredded hornbeam (Carpinus betulus) Pollarded hornbeam (Carpinus betulus)

Bunch hornbeam (Carpinus betulus) Oak and beech – twins, planted together (Quercus robur, Fagus sylvatica)

8 Plate 2

Oak dead wood Tinder fungus (Fomes fomentarius) on beech

Tinder fungus (Fomes fomentarius) in detail

Heartwood affected by blight Sapwood (oak)

9 On the other hand, already in the middle of Around the protected area the forest is still the 19th century the public interest in the today endangered by the activity of the brick beauties of this old forest started and as a industry which for centuries has been using consequence the central part, the Urwald the weathered uppermost 2 m of the Lauen- area, was protected in the way that any utili- burg clay for bricks of excellent quality. zation apart from grazing was forbidden. Now also recreation became a topic for the society and the middle classes discovered a passion to promenade, for which this old forest with its bizarre oaks and beautiful tree ensembles became a favourite target. A strict nature protection regulation prohibiting forest activities, which has been intensified by law since 1938, lead to the strong spread of beech. This was enforced by the old drainage system, which favours Fagus in its competition against Quercus. The beeches occupied the open areas and soon overgrew the oaks so that many of these died. Nowadays the succession towards the potential natural forest has more or less finished in most parts of the protected area; some of the dead oak trunks are still standing upright, others have fallen down. In the underwood there took place a considerable expansion of Ilex aquifolium, favoured not only by the oceanic climate of the coastal region, but also by the advantage of having been present in the forest from the beginning, but being rather resistant to grazing. There exist impressive trees of Ilex with a height up to 15 m and a trunk diameter up to 29 cm. Nowadays this old forest is one of the very few historic woodlands in Germany, where the different ways of former forest utilization such as pollarding and coppicing can be studied. Pollarding for instance often led to peculiar trees with a stump carrying several stems and forming typical candelabra. Some of the deformed trees, broken down, give the impression of dangerous ghosts, especially at night. Perhaps the most important treasure of the Urwald is the large amount of dead wood that offers special biotopes for some plants and many animals, in particular fungi, birds and insects.

10 EXCURSION STOP 2

The East Frisian Central Bog – a fragmented archive of natural and anthropogenic landscape development Steffen Wolters, Karl-Ernst Behre & Michael O’Connell

The East Frisian Central Bog is a vast com- The middle part of the East Frisian Central plex of raised bogs located on the ridge of Bog complex is occupied by three adjacent the Oldenburgisch-Ostfriesische Geest land- nature reserves, namely the bogs Lengener scape in the northern part of Lower Saxony, Meer, Stapeler Moor and Spolsener Moor. a region which was once extremely rich in Whereas Lengener Meer represents to some mires. Bogs and fens covered ca. one third extent a near-natural bog relic with a large of the territory of East Frisia as well as of bog pond, Stapeler Moor shows the results Oldenburg, most of them being raised bogs. of 15 year long renaturation efforts after Despite continued cultivation Lower Saxony industrial peat cutting was stopped in 1997. still boasts 2.500 km² raised bog, represent- Spolsener Moor in the NE of the complex ing 73.5 % of Germany’s total bog area. was affected by private farmers peat cutting.

Distribution of bogs (black) and fens (dotted) in The nature reserves Lengener Meer, Stapeler northwestern Lower Saxony and the East Frisian Moor and Spolsener Moor as seen in Google Central Bog Earth. The red cross indicates stop 2.

Bogs and fens The mires of NW Lower Saxony fall into fen belt follows this line and is referred to as two distinct categories, namely fens (Nieder- Geestrandmoore. Fens also occur along moore) and raised bogs (Hochmoore). small rivers, in many of the valleys, and in Most of the fens were initiated by the rising depressions on the Geest. sea level and spread across large areas. Their Northwestern Lower Saxony has been very growth was sometimes interrupted by the much the land of raised bogs which deposition of marine or brackish clay upon occupied huge areas in the region. Their them. In the areas of greatest distance from formation started in most places during the the coast, i. e. along the Geest or Pleistocene late Atlantic or in the Subboreal period. The margin, drainage is worst. Consequently, a initiation of ombrotrophic mire development

11 was mainly triggered by changing climatic conditions at that time. It was not only, however, the effect of the beginning of a general climatic deterioration but, in this region, also the effect of the Flandrian transgression that had reached the position of the modern coastal area during the Atlantic period. In many places the raised bogs are preceded by fen peat. This suggests that the change to formation of Sphagnum peat is a clear indication of a changing water budget. In large areas the formation of raised bogs commenced directly on the mineral soil without an intermediate phase, i. e. the bogs replaced woodland. These raised bogs are referred to as wurzelechte Hochmoore which The Moorprojekt of the NIhK. is literally 'raised bog genuine to the very The oldest, average and youngest start of raised roots'. bog formation is given in years cal. BP.

Spolsener Moor: Vegetation and land use history Pollen analytical investigations were under- undershrub and Alnus is important, pre- taken by O’CONNELL (1986) with a view to sumably in the wetter areas. The edaphically reconstructing vegetation and land-use more demanding trees of the so-called mixed history in the Neuenburg area, i. e. the oak forest, namely, Ulmus (c. 4%), Fraxinus Friesische Wehde. The profile was taken and Tilia (c. 3 and 2%, respectively) do not from a remaining small island of peat which appear to have responded to the more is surrounded today by agricultural land favourable local edaphic conditions provided reclaimed after peat cutting. At the time of by the Lauenburger Ton. maximum bog extension, the Geest lay some The first major change in woodland compo- 2.5 km to the east of the sampling point. sition is signalled by the rise in Fagus to The 368 cm long profile spans the period over 1% and the initiation of a continuous from late Atlantic (c. 5000 B.C.) to recent curve for Carpinus at 2000 B.C. This signals times. The basal 50 cm consists of sand a limited expansion of beech and the spread overlain by Phragmites peat. The pollen of hornbeam into the area. These two trees spectra from the sand show high Pinus and expand in a stepwise fashion, first at Alnus values (c. 30%; all values as % A.P. 900 B.C. and then at A.D. 200. and with excl. Corylus). Spectra from the Phragmites Fagus achieving maximum representation at peat reflect mainly local mire vegetation A.D. 800, i. e. prior to large scale Medieval with alder being replaced by birch carr woodland clearance. which suggests a shift towards oligotrophic Trees that show decline include Ulmus (but conditions. the Elm Decline is not well defined), Tilia With the transition to raised bog peat (pre and Pinus. Lime and pine probably became 4000 B.C.), A.P. curves are no longer dis- extinct, the former being re-introduced for torted by high local pollen producers. Quer- bast lime in the Medieval period and the cus (presumably Q. robur) is the dominant latter being widely planted from the earlier tree of the mineral soils, Corylus is the main part of the 18th century onwards.

12 13 In the lower part of the profile, anthropo- probably in response to anthropogenic genic indicators are poorly represented. activity. Occasionally Cerealia-type pollen is 3. A general trend towards increasing human recorded in pre-Elm Decline levels but the impact is maintained until the 6th century significance of these records as indicators of A.D., when there is a noticeable decline in arable farming and hence of a Neolithic anthropogenic indicator curves (cf. presence is open to question. A continuous P. lanceolata, Pteridium and Chenopodia- P. lanceolata curve begins above the level ceae) and Fagus and Carpinus begin the fi- ascribable to the Elm Decline. In the middle nal phase of expansion. This is the so-called and upper parts of the profile, the following Siedlungslücke or 'habitation gap' when, in features relating to land-use and human both the coastal Marsch area and the Geest, impact are noteworthy: the population levels declined dramatically 1. The decline in Tilia and the first expan- until the 8th century A.D. It is noteworthy sion of Fagus and the spread of Carpinus that the Cerealia curve is uninterrupted (2000 B.C.) is seen in terms of Bronze Age which indicates that arable farming did not interference with the previously more or less cease; the region cannot therefore be re- undisturbed Quercus-dominated woodlands garded as devoid of habitation. (cf. Pteridium and Artemisia). 4. In the uppermost PAZ (LEN V-5) a dra- 2. In the late Bronze Age/Early (pre-Roman) matic rise is recorded in the anthropogenic Iron Age, i.e. from 800 B.C. onwards , the indicator curves (cf. Secale, P. lanceolata diversity and representation of anthropo- and Fagopyrum; also the Cannabis/Humulus genic indicators increase (cf.. Cerealia-type, curve) and A.P., except Pinus, decline. Here Artemisia, P. lanceolata and P. major/ the intensive cultivation of rye, which began media) and woodland composition shifts in in the Middle Ages (c. A.D. 1000), and of favour of beech, with a substantial decline in buckwheat is clearly reflected in the pollen hazel. These woodland changes take place spectra.

Raised bog expansion and trackways crossing the bog The expansion of the raised bogs mainly in A few show a considerable length and they Subboreal times resulted in a considerable seem to belong to an extended system of reduction of the woodland in the region and traffic routes. A more than 3 km long linear also of the territory available for prehistoric trackway was excavated in the northern part settlements. The original size of several of of the East Frisian Central Bog and dates to the raised bogs exceeded 100 km² the 3rd millennium B.C. A track width of 4 m and finds of numerous wagon parts, e. g. From the Elbe-Weser area we have several axles and wheel remains, give evidence to impressive examples which show how the the trafficability of the trackway. expanding bog overgrew prehistoric sites, including megalithic tombs. Many of the Trackways from the 4th and 3rd millennium overgrown artifacts and archaeological B.C. mostly consisted of Alnus and/or Betula features were discovered in the course of wood but from the Bronze Age onwards peat cutting in modern times which also Quercus prevailed. Pinus, Populus and revealed wooden trackways and more Fraxinus were rarely used. The preservation unusual items such as bog corpses. Wooden conditions of wooden trackways vary and trackways were built to bridge the strongly depend on the extent of bog drain- increasingly boggy ground and date in East age and peat desiccation. Many have already Frisia from the Neolithic to Medieval times. fallen victim to widespread bog cultivation.

Map of Oltmannsfehn-Ockenhausen Wooden trackway from the early Bronze Age Two prehistoric wooden trackways and one Another adaptation to an enhanced bog medieval way made of peat sods are known growth is mirrored in the greater length of from the immediate vicinity of the excursion the trackway (B), because the bog passage to site. The older wooden trackway (A) is bridge has considerably expanded since the 2,5 m wide and made of carefully debranch- construction of the first trackway. ed alder and birch trunks. It was constructed in the early Bronze Age. The structural design is simple comprising only of adjoin- ing round timbers resting on longitudinal timbers without any supporting stakes. This strongly contrasts with the more sophisticated architecture of the younger (7th century B.C.) and longer wooden trackway (B–C) which was recorded only 140 m to the west. The carriageway consists of square oak planks supported beneath and above by longitudinal timbers. The whole construction is fixed by regularly upright inserted perforated wooden stakes. The sophisticated architecture is an adaptation to an enhanced peat growth which commenced at the transition Subboreal/Subatlantic. It it kept the planks in compound structure during strong oscillations of the bog surface due to the interplay of increased water absorption th and drying-up. Wooden trackway from the 7 century B.C.

15 The Schwarz-Weisstorf-Kontakt Most of the raised bogs in the area show a a considerable change in the water balance marked stratigraphic division into the lower towards wet conditions. dark peat and the upper light-coloured peat, This phenomenon was first described by separated by a clear recurrence surface. C. A. Weber already in the 19th century and While the dark peat (Schwarztorf) is highly was referred to as Grenzhorizont. He assu- decomposed and normally contains only few med an interruption in peat formation had identifiable macroscopic plant remains, the taken place over about 1000 years, cor- light-coloured peat (Weisstorf) has only a responding to the Subboreal period. Since low degree of humification with macro re- then, much new evidence has resulted in mains which can easily be identified. The these early views being considerably modi- Schwarztorf often ends with a peat layer rich fied. Pollen diagrams, as well as 14C-dates, in Eriophorum and Ericaceae deposited un- indicate that there was definitely no inter- der relatively dry conditions. The following ruption of peat formation at this recurrence Weisstorf on the contrary starts with a layer surface; the old term Grenzhorizont is no of Sphagnum sect. Cuspidata often with longer used and has been replaced by the Scheuchzeria. This marked recurrence sur- neutral Schwarz-Weisstorf-Kontakt (black- face (some profiles have several but rather light peat contact). indistinct recurrence surfaces) is the result of

Schwarz-Weisstorf-Kontakt (Black-light peat contact) Over the last decades, dating of this recur- It is evident that the change in the water rence surface by pollen analysis and 14C balance is caused by the general climatic have been obtained from many places in deterioration in the last millennium B.C. northern Lower Saxony. They range from Depending on factors such as drainage the late Neolithic to early Medieval times. systems in the bog and the conditions of Most dates, however, are concentrated discharge outside the bog, the timing of the between 800 B.C. and A.D. 100 and with change of peat formation may vary increased frequencies around 700 B.C. and considerably between different bogs. around A.D. Marked differences in the change of the

16 water balance also occurs within large bog below the recurrence surface in parts of a systems, as demonstrated in several cases by bog and above in other parts of the same pollen and 14C-dates. Excavations of wooden bog, showing that the precise age of the trackways effectively support these results. recurrence surface in one bog is strongly Some trackways have been recorded running dependent on the local hydrology.

Peat cutting and bog cultivation Peat bogs have been the main source for fuel the overlying light-coloured peat, so that the in the coastal area for a long time. The Clay peat diggers dug pits to recover the dark peat District and most of the Geest were almost and then filled the holes with the light peat treeless in the late Middle Ages and well which was not used. into Modern times. Thus peat was urgently This unregulated peat cutting was continued needed for fuel. The thermal value of the until after World War II and is still practised lower black peat is much higher than that of in some remote areas.

Modern peat-cutting site with fuel peat

In the early 17th century another, more sys- poor in nutrients, the farmed soils had to be tematic way of peat cutting and subsequent improved by the supply of suitable mineral cultivation was introduced from the Nether- and organic materials, which included sand, lands: the Fehnkultur. For this method of fluvial deposits, manure and litter. These fuel production and cultivation, large areas materials were transported on the return trip of raised bogs were given to private compa- of the boats which were used to export the nies. They drained the bogs with long ca- peat. The farmers, like the bog plots they nals, subdivided the area and gave the plots were given to farm, were extremely poor; of raised bog to farmers as private property. the only crops they could grow on these soils These colonists excavated the black peat, were buckwheat and rye as well as some starting at the canals, and sold it in the potatoes and oats. Nowadays, these so-called neighbouring towns like Emden, Bremen, Fehnsiedlungen with their long and often etc. The excavated parts, filled up with the branched canals and corresponding rows of light peat that remained after the cutting, farmhouses, form a characteristic part of the were used for agriculture. Meadows and East Frisian landscape, their inhabitants pastures as well as fields were established on being employed outside agriculture, e. g. in these grounds. As bog moss peat is very industry, shipping etc.

17 Another important form of utilization of This form of utilization could be continued raised bogs for arable farming has been the for only 6 to 7 years in succession due to the burning of the bog surface which came into exhaustion of the soil; after this a break of use towards the end of the 17th century. The 30 years was necessary before a new phase bogs were drained without preceding peat of cultivation could be initiated. The cutting and the surface burned after drying. Lengener Moor still shows distinct traces of Mainly Fagopyrum was grown, which was this type of bog exploitation. sown virtually into the ash. Peat burning was practised on such a large scale that air pollution during the burning season in May was registered in far distant places such as England and Poland. There were strong public objections against this practice and, already in the 19th century, the 'Bremen Association Against Bog Burning' was founded, which probably represents the first organised ecological (green) movement. Finally, this practice was outlawed in the th early years of the 20 century but by then most of the raised bogs in Niedersachsen Bog burning as preparation for buckwheat sowing. Wood engraving by VAN DEIST c. 1880 were affected by it.

Map showing the distribution of smoke caused by bog burning (PRESTEL 1868) From the last century onwards, modern remaining. This included large areas which, techniques for the cultivation of raised bogs after peat cutting, had remained as waste were introduced, developed and promoted land. Using huge plough shares, the by the famous Moorversuchsstation Bremen. underlying sand was ploughed-up and mixed The first was the 'mixed sand cultivation' with the peat thus leading to a considerable (Sandmischkultur) that could be applied to improvement of the soil. bogs with a depth of up to 1.20 m of peat

18 Another method was the German raised bog cultivation or Deutsche Hochmoorkultur that was carried out on the virgin raised bog where no peat cutting had taken place. The areas were drained and had to be intensely fertilized. This was done first by the application of ordinary manure, and complemented by the growing of legumes to improve the nitrogen content and later by applying artificial fertilizers. Sphagnum peat has turned out to be a very suitable substratum for agricultural purposes and is Long rows of light peat (Weisstorf) valued even today, though it needs large prepared for drying quantities of fertilizers to maintain its After the decline of peat production for fuel productivity. some raised bog areas have been used on a large scale for the production of peat for Fuel peat cutting became an industrial extent th gardens and for horticulture. In this case the towards the end of the 19 century. A peat light peat is removed, dried and prepared for power plant was built 1908 in Wiesmoor horticultural use as 'peat moss' while the which also burned fuel peat from the black peat is left untouched. Stapeler Moor, a more or less unused raised bog at that time. Next to electricity the peat This industrial peat cutting is carried out in power plant produced heat for the numerous machined surfaces several km2 in extent. greenhouses in the region. It shut down in The exploitation of such an area takes 1964. During peak production the daily between 15 and 30 years, after which it must demand of fuel peat added up to c. 400 tons. by law be cultivated or regenerated as bog.

Nature conservation and bog flora For several years now all remaining bogs in Today, very few and then only small Lower Saxony which, in general, are very remains of more or less untouched raised limited in extent or form only tiny parts of bogs remain. In general they show the former large bogs, are protected by law. typical hummock-hollow morphology. It is New permissions for peat cutting or not certain, however, whether this cultivation are not granted. In several places, morphological feature is a natural primary regeneration measures in former raised bogs one, because it is best developed when a have been undertaken by the authorities in certain amount of drying out has taken place. the interests of nature conservation – only Only few salient facts will be given the next generation can judge if these have regarding the modern vegetation of raised been appropriate and successful. bogs. Under natural conditions Sphagnum species are dominant; in the area north of Bremen, S. imbricatum and, less frequently, S. papillosum are the main constituents of the light peat. At the latitude of Bremen there is a sharp boundary; south of this, S. imbricatum disappears and is replaced by Sphagna acutifolia while S. magellanicum Bog renaturation in the Stapeler Moor and S. cuspidatum are present throughout the

19 region. Investigations of modern raised bogs indicate that there has been a strong decline in the occurrence of S. imbricatum over recent decades. Compared with more continental raised bogs it should be noted that the ombrotrophic bogs in the coastal area have a slightly higher content of minerals due to the salt which is blown in from the sea. Thus, for instance, Eriophorum angustifolium is regarded in the north-western part of the region as a character species of typical raised bog vegetation, while, in the Harz Mountains, it indicates slight minerotrophic conditions compared with the more oligotrophic (and purer) stands in that area. Three other bog species should be mentioned: Erica tetralix, Narthecium Narthecium ossifragum ossifragum and Myrica gale, all of them oceanic elements which are common in northern Lower Saxony but restricted to this area and not occurring south of Hannover. They normally expand after the bogs have been drained for some time.

Literature:

O’CONNELL, M., 1986: Pollenanalytische Unter- suchungen zur Vegetations- und Siedlungsgeschichte aus dem Lengener Moor, Friesland (Niedersachsen). Probleme der Küstenforschung im südlichen Nordseegebiet 16, 171-193.

Eriophorum angustifolium

20 EXCURSION STOP 3

The Sehestedter Moor – a uniqe mobile geological monument at the Jade Bay Karl-Ernst Behre

The Sehestedter Moor, a raised bog outside wood peat and during the next decline of the the dike, represents the remnants of an sea level shortly before the Birth of Christ, it extensive raised bog which originally changed to a raised bog, dominated by covered large areas on both sides of the Sphagnum. This development to a bog, present dike. Its formation started, when the which grows independently of the ground predecessor of the present Jade-Bay, the Ur- water, was caused by the lowering of the Jade Bay, silted up. Between 1500 and 1000 ground water, as consequence of the sea B.C. there was a regression phase in the level decline. Behind the elevated levee North Sea and the whole area turned from along the coastline a huge backswamp area marine to freshwater conditions resulting in existed until the Middle Ages, when the Jade swamps and the formation of fen peat. The Bay was formed (see the different stages of hydroseral succession led further to brush- the formation of the Jade Bay next page).

Aerial photography of the raised bog outside the dike and the cultivated part inside

The formation of the Jade Bay started in the it floats up on the seaward side. Because the early 13th century, when storm surges broke body of the raised bog is completely filled through the elevated levees and flooded the with fresh water and the part along the cliff low-lying backswamps. Many storm floods is dried out, it is lighter than sea water and continuously eroded the peat bogs and rises. In this way it protects the hinterland. enlarged the bay step by step until it Before diking this phenomenon of the float- extended far beyond its present size and had ing of raised bogs was quite common and even connections with the Weser river. happened later outside the dikes. This is A very special way of resistance prevents documented by the occurrence of clay layers the raised bog from being flooded and cov- within the bogs which are frequently record- ered with sediments: during high storm tides ed in corings from the Clay District of Ger-

21 many, the Netherlands and elsewhere, and tore off and drifted away until they stranded which are called Klappklei (~turn up clay). somewhere else. This occurred also in other Nowadays the Sehestedter Moor is the only places along the southern North Sea. There place at least in Europe, where this specific are several written sources about this phenomenon can still be studied and thus phenomenon and a very impressive one tells provides the explanation for the special us that during the tremendous flood of 1509 geological phenomenon of the Klappklei. a large plot of peat bog, carrying 12 cattle, drifted more than 15 km from the Dutch In the course of the last centuries the area of west side of the Dollart to the German this bog has been considerably reduced by eastern shore where it stranded. erosion. Sometimes parts of several hectares

22 The development of the Jade area since the Birth of Christ

For many centuries the southeastern part of refuge for plants and animals, it had been the Jade Bay was not protected by dikes as decided not to protect it in order to preserve all the other regions along the coast but by this unique mechanism of a floating bog the floating up of the raised bog. which lacks any counterpart. The floating of this bog takes place when the level of a storm flood reaches 1,70 m above mean high water. This is not the case in every winter; there have been many years without floating, in the most recent years, however, there were several severe floods and the bog floated up. In winter 2006/2007 this occurred even three times, causing most severe damage. Nov 1st 2006 during a huge gale the bog was lifted and the complete southern part was torn off and drifted around 5 m southwards and also up onto the dike. At its edges peat walls bulged, while along the separation line in the bog a channel came into existence which now runs at right angle across the whole bog to the dike.

Map of the south-eastern Jade Bay ca. AD 1620

Only in 1725 a dike across the bog was built and for this an exact survey was carried out. So we know that in 1722 the extension of the Sehestedt bog which was left outside the dike amounted to 165 ha. At that time there still lived several farmers on the bog where they raised sheep and had small fields. During storm floods their houses were lifted together with the bog and these farmers were more safe than their relatives behind the dikes that sometimes broke. The last inhabited farmhouse outside the dike was destroyed only in 1908, not by the sea but by lightning. The erosion of the Außendeichsmoor (=bog outside the dike) continued further and further and its size was reduced to 107 ha in 1820, 21 ha in 1932 and only 9.6 ha nowadays. Although this bog is an important

23 Holocene sequence at the bog

Cross section of the Sehestedt bog

When the bog floats up during storm surges, chunks up to more than 10 m in length are waves, driven by the gale, bounce against torn off and drift to the north and south. This the bog and strong erosion takes place. Peat is the way in which fresh and steep forms of

24 the cliff are created and maintained. During below and the Sphagnum peat of the raised years without uplift the cliff slopes and bog above. Then a hollow develops into becomes overgrown by plants. When it which the water intrudes. Within minutes floats up, the bog tears off exactly at the this churned up water calmes down boundary between the fen and the carr peat completely and loses its transport ability.

Opening-up of the Sehestedt bog and the formation of Klappklei above: floating at severe storm floods below: normal position which is demonstrated by pollen analyses of the clay compared with those from the peat. When the sea retreats after the storm, the bog drops into its former position. Now many torn off peat chunks are scattered in front of the cliff; they will be eroded in the course of the next years.

Storm flood at the cliff of the bog Now for many hours the dispersed clay and sand particles are deposited inside the bog and form the Klappklei. With each floating up this Klappklei increases in thickness and reaches in places up to more than 30 cm. This clay layer is sharply delimited at the top and the bottom as can be seen in many corings in this bog and elsewhere along the Just eroded peat chunks coast. It is younger than the peat above,

25 By now the Sehestedt bog has become very That includes more than ten Sphagnum small, but in its area it still protects the coast species, two species of Drosera as well as and the dike behind it is one meter lower Rhynchospora alba. It is also a refuge for than north and south of it. It is estimated that several rare birds and many small animals. it helps to protect the dike until about 2040 For the vegetation history the Sehestedter and that smaller parts of the Sehestedt bog Moor is a very important archive as it is the may withstand until the end of this century. last remnant of the former huge bog and the only place in a wide region where a pollen diagram could be elaborated. The pollen diagram is presented here in a short form only (for the full diagram see BEHRE & KUČAN 1999). Apart from the youngest part, when the raised bog became smaller and was even cultivated in some parts, the pollen diagram shows the local bog vegetation, which produces only little pollen, and the pollen input from the wide area around from Peat cliff in the southern part of the bog where mainly the tree pollen came. Nowadays everywhere along the coast the In the lowest part of the diagram the vicinity dikes are increased to meet the expected rise of brackish or marine environments can be of the sea level. Such dikes have to be con- seen, expressed in the declining curve of structed much broader because of the soft Chenopodiaceae. The tree pollen of the clay underground. In this special case it Klappklei layer (see also the detail diagram) would mean that about half of the bog would is characterized by high percentages of have to be given up. To avoid this, an iron Pinus, which is common in marine sheet-pile wall was driven into the dike to sediments as well as some Picea, not native provide additional safety. in NW Germany and occurring here as Apart from its eminent geological value the redeposited and far distance transport. Sehestedter Moor is also very important for Important is the record of Juglans, Secale plants and animals. Although it dries out (up to 2%!) and Centaurea cyanus long continuously and is influenced by salt spume before these species reached this region. during storm floods it is still ombrotrophic They confirm that the material of this layer in large parts and several typical plants of is younger than the peat above, where these the raised bog have survived, species disappear again. There are two 14C- dates from below and above the clay layer: 2190±70 respective 2180±75 years BP. The upper part of the pollen diagram shows the history of agriculture upon the bog and around. The start of the Secale curve points to the rye cultivation on the Pleistocene ground 10 km away, but since the Late Medieval period, when Secale reaches remarkable 31 %, rye was grown on the peatbog itself, together with Avena strigosa Bog surface in spring with Myrica gale (hidden in Cerealia p.p.), which is supported by written sources. Later also Fagopyrum

26 esculentum was cultivated here, which at that time was a common fruit on the poor soils of the raised bogs in NW Germany and the Netherlands. Cannabis on the other hand has never been grown on the bog, but in the Clay District around, where Medieval macro-remains were found. The considerable increase of Poaceae indicate the cultivation of small parts of the bog for grazing, for which as for the fields, manuring was necessary. Together with Chenopodiaceae the grasses also show that the salt marshes came closer to the coring point in the course of the destruction of the bog. The Sehestedter Moor has been a nature reserve since 1938 and is strictly protected. 1986 it became part of the national park Niedersächsisches Wattenmeer, together with all salt marshes around the Jade Bay. Only in 2007 a wooden trackway was constructed along the southern margin of the bog in order to open it at least slightly for the public.

Literature:

BEHRE, K.-E. and KUČAN, D., 1999: Neue Untersuchungen am Außendeichsmoor bei Sehestedt am Jadebusen. Probleme der Küstenforschung im südlichen Nordseegebiet 26, 35-64.

BEHRE, K.-E., 2005: Das Moor von Sehestedt. Landschaftsgeschichte am östlichen Jadebusen. Oldenburger Forschungen, NF 21, 145 pp.

27 Plate 3

Stratigraphy with Klappklei Pollen diagram: Detail from the Klappklei

Pollen diagram Sehestedt bog

Aerial photography of the Sehestedt Außendeichsmoor from 2003

29 EXCURSION STOP 4

The Wurt Sillens – settlement, dike-construction and archaeobotany Felix Bittmann & Johannes Ey

Prehistoric settlements at Butjadingen, District of Wesermarsch From 500 up to 200 B.C. the Dünkirchen I- to 17 m long and 5 to 7 m wide. From the transgression built up the southern levee at 1st century A.D. onwards the Dünkirchen II- Butjadingen. But in the 1st century B.C. a transgression formed the northern levee at regression occurred, which formed a fossil Butjadingen. Both levees, curving and soil beneath the present day surface. The ex- stretching parallel to each other, had obvi- cavation at the Wurt Einswarden proved ously been excellent for settling, in west- housing estates situated upon the levee of east-direction the southern levee bearing the the Weser at ground level representing the Wurten villages of Mengershausen, See- first stage of settlement around 100 B.C. verns, Süllwarden, Sillens and Einswarden, There had been three-aisled houses com- the northern one those of Tossens, Ruhwar- bining living quarters and stables, being 10 den, Langwarden, Tettens und Blexen.

Low lying marshes (Sietland), levees and Wurten in northwest Butjadingen

Excavations at Seeverns as well as at Süll- for about 1 m. The Dünkirchen II-transgres- warden and Sillens proved interesting results sion forced the farmers to rise the level of concerning the stratigraphy of the prehistoric dwelling during the 1st century A.D. So ex- Wurten. At Süllwarden there was a settle- cavation trenches cut into the central Wurt ment layer at ground level of +1.20 m NN. proved six levels of dwelling which had At Sillens the first stage of settlement been risen artificially by up to 3 m within around the Birth of Christ was at a level of this period, which was dated by ceramic and +1.40 m NN which was raised by manure metal finds.

29 As the arable land around the locations on There, excavations at Langwarden and the southern levee was getting wet during Ruhwarden proved that settling at ground the 2nd century A.D., the farmers of the Wur- level started not until the 3rd century A.D. ten villages moved for about 2.5 km to the Later on increasing threats by storm floods north towards the coastline, settling on the forced to raise the dwelling levels here as northern levee, silted up in the meantime. well.

Re-occupation in the Early Middle Ages From the 7th century A.D. onwards a regres- 9th century A.D. by bronze needles. During sion allowed to settle again in the salt the early 8th century the dwelling level on marshes which had been nearly abandoned the north side of Sillens was raised up to during the 6th century A.D. On the one hand, +4.20 m NN. On the other hand freshly prehistoric Wurten had been resettled, as it silted up marshes had been settled at ground was the case on the south side of Sillens at a level, for instance in the case of the village level of ca. +3.80 m NN. Corresponding Wurt Niens, parish of Langwarden. graves were dated to the early

Expansion of fields during the High Middle Ages and changes in Modern Times As in most of the Wurten villages, also at Sillens previously more farms existed than today. Since the 11th to 12th centuries the growing population forced to enlarge dwelling and economic areas in the Clay District (Marsch). Therefore, during the 12th century the Wurt Sillens had been again enlarged artificially by clay on its top as well as on its southern edge. By this, its top rose up to +4.90 m NN and its basement diameter increased to about 280 m. Additionally, grange Wurten had been established in the near surrounding which could be dated by ceramic finds to the 12th to 13th centuries. The wealthy farmers of Sillens probably had been responsible for that colonization. In the 18th century there has been documen- tary evidence for craftsmen besides of peas- ants dwelling at Sillens. Section through the medieval extension of the Wurt Sillens

Initiation of dike-construction in Lower Saxony Due to the rising watertable of the North Sea archaeological and written sources. the people of the coastal marshes started to Archaeological investigations of medieval protect their agricultural land against storm dike remainders reveal that those dikes floods from the 11th century onwards by consisted entirely of clay sods and that they dikes. Research on early dikes relies on had gentle seaward slopes. The first written

30 evidence of dike construction in the German In Lower Saxony ring-shaped dikes have coastal area is found in the legal statutes of been traced for instance at the Wurten the Frisian people, ‘Siebzehn Küren’ villages of Oldorf, District of Friesland, and (Seventeen Elections) of the late 11th of Sillens. As it was demonstrated by field century. During this early period ring-shaped system analysis around Sillens, the dike was dikes were built, as this type of dike embracing the Wurt, encircling an area of ca. represents the most simple one. It encircled 80 ha. Two archaeological sections proved the infield area of each village community this dike as well. Three Wurten already so protecting its arable land against flooding, established in the 1st century A.D. had been and it did not cross any streamlets. Therefore also located within the enclosed space. this early phase of dike construction must The Sietwendungen (rectangular low dikes) have been organized and later on maintained have been historically established since by each Wurten village community of its approx. 1200 A.D. and were designed to own. Due to recent research the water table th channel the effluent waters from geest and of the winter storm floods during the 11 bog areas, by that running orthogonal to the century was only up to about one metre coastline. They must have been constructed above the mean high water table. Those by the in each case adjacent parishes. early dikes probably towered its surrounding area by about 1 m and thus the mean high Continuous coastal dikes, which ran parallel water table by about 1.4 m, so presumably to the shoreline of the North Sea, were built th protecting settlements and agricultural land since the 13 century. This work must have even against the high, more dangerous been planned and accomplished at a larger winter storm floods. scale by the Frisian Republics which represented all parishes of the region.

Sillens, District of Wesermarsch, Lower Saxony: Construction of a dike. Oldenburg manuscript of Ring-shaped dike (probably 11th century) and “Sachsenspiegel“, dated 1336 A.D. phases of expanding agricultural area and diking

31 For piping water through a dike from the landward to its seaward side, mainly wooden sluices had been constructed. The oldest one from Lower Saxony was found at Stollhammer Ahndeich, Butjadingen. It dates earlier than 1362 and was at least 14 m in length. Its seaward part was made of a hollowed oak trunk, which had an internal width of approx. 0.8 m at its mouth. At high tide its lid lowered automatically to prevent the rising water from running inland. The sluice’s landward part consisted of a channel made of oak wood, which had a weir and a slide for regulating the water table in the ditches landward of the dike. In Schleswig-Holstein an even older wooden sluice from Rungholt, Northern Frisia, was documented. It was built not earlier than approx. 1200 A.D. and had two pipes, each of a width of 1.30 m, at a length of 20.50 m. Sluice made of oak wood, Stollhammer Ahndeich. Built before 1362 A.D.

Archaeobotany Excavations of the dwelling mound Sillens in 1987 revealed organic layers dated to the 1st century A.D. up to Medieval times. Those dwelling mounds had been built on elevated levees of the coastal zone starting around the Birth of Christ. Some of these in the Butjadingen peninsula have been explored, partly excavation trenches were dug and samples were stored in our institute. Currently these samples are Wurten of Langeness, an example from the Northern Frisian Islands analysed to get a better insight into the early “Wurtenphase” and its economy in comparison to the western part of the East- Frisian Peninsula at the border to the Netherlands (e.g. Rysum) and in the Wangerland north of Wilhelmshaven where several dwelling mounds (“Wurten” or “Warften”) have been investigated during the last decades.

The Wurt Rysum

32 In the early stages, such dwelling mounds were raised by layers of organic material consisting of chaff, garbage and litter to withstand the rising sea-level, later sods of clay were used. Therefore the organic layers, if well dated, can also be used to reconstruct former sea-level stands. We differentiate two phases interrupted by the Migration Period when the sea-level was rather low but people had left the area. Starting with settlements on flat ground the house places were raised several times parallel to the rising sea-level. After the Migra- tion Period the same cycle took place until in A.D. 1300 a closed line of dikes existed along the coast (see figure in the Introduc- tion). In its shelter, people could settle on flat ground again, but now the settlements were threatened by dike breaches. Fresh sediments are henceforth deposited only in front of the dikes, behind no sediments arrive anymore. In addition the surface Excavation 1987, showing several organic layers of behind the dikes was lowered by drainage Roman Iron Age at the base of the trench causing peat compaction in the underground, by peat cutting for selnering and by removal of clay for dike building. The difference Salt marsh between both parts is increasing until today Aster tripolium Se/Fr 47 and will further increase in the future (unless Atriplex littoralis/hastata Se/Fr 832/1* the dikes would be taken away…) Centaurium cf. littorale Se/Fr 33 Currently 26 samples (each about 10 l) dated Glaux maritima Se/Fr 41 to the 1st century A.D. from the Wurt Sillens Glaux maritima Cap 12 with more than 250.000 remains (about Juncus gerardii Se/Fr 115.085 200.000 seeds and fruits) have been ana- Juncus gerardii Cap 28 lysed, resulting in concentrations of about Plantago maritima Se/Fr 180 20.000/l (25.000 identified remains/l). Due Plantago maritima Cap 430 to the high groundwater level, excellent Puccinellia distans Se/Fr 211 preservation conditions prevail (water- Salicornia europaea Se/Fr 114 logged) and the majority of the material is Samolus valerandi Se/Fr 16 uncarbonised. Scirpus maritimus Se/Fr 475/1* This enormous values of diaspores are due Spergularia media Se/Fr 112 to the seeds of Juncus gerardi (more than Spergularia salina Se/Fr 2265 50%) characteristic of the Juncetum gerardii, Suaeda maritima Se/Fr 47 a typical plant community of the salt marshes. Because trees could not grow un- Triglochin maritimum Se/Fr 6.521 der the conditions of the salt marshes, herbs Foraminifera Shell 96 and grasses are the most important plants. * charred, Se/FR – seed/fruit, Cap - capsule

33 Cereals were found in low quantities, both which is the oldest known settlement in the charred and uncharred. The most important German Clay District, it is evidenced by cultivated species probably was Linum (flax) thick layers of pure remnants of Camelina. and also Vicia faba has been grown as Triticum dicoccum and T. monococcum can evidenced by its stems and pieces of the also withstand a certain amount of salt in the pods and peduncles. soil, therefore these can be found regularly in the archaeobotanical samples up to the Cultural plants Medieval. Secale (rye) cannot grow on such Camelina sativa Se/Fr 43 soils, it is therefore restricted to the sandy Camelina sativa Sil 53 Pleistocene hinterland with its poor and Hordeum vulgare Se/Fr 38/10* sandy soils. Hordeum vulgare Rac 255/7* The wet conditions are furthermore Linum usitatissimum Se/Fr 1.299 evidenced by many species of river banks Linum usitatissimum Cap 1.146 (among non-cultivated taxa only those with Linum usitatissimum Stem 8.554 more than 10 finds are shown). Triticum dicoccum Glume 13 Triticum dicoccum Spiklet 3 River banks Vicia faba Se/Fr 1 Berula erecta Se/Fr 118 Vicia faba Stem 253 Bidens tripartita Se/Fr 20 * charred, Rac – rachis, Sil – siliqua Carex paniculata Se/Fr 12 Carex riparia Se/Fr 62 In the frame of cultivation experiments in Eleocharis palustris agg. Se/Fr 378/2* 1961, Linum, Camelina, Hordeum and Vicia Erica tetralix Leaflet 21 faba have been grown in the salt marsh. Eriophorum vaginatum Skl 18 Flooding reduced the harvest but not Galium palustre Se/Fr 109/1* damaged it totally showing that agriculture Juncus bufonius Se/Fr 672 in that area was possible, although cattle Juncus effusus Se/Fr 192 breeding had been predominant. Lycopus europaeus s.l. Se/Fr 22 Lythrum salicaria Se/Fr 1.049 Mentha aquatica/arvensis Se/Fr 750 Oenanthe aquatica Se/Fr 56 Oenanthe lachenalii Se/Fr 282 Phalaris arundinacea Se/Fr 65 Phragmites Se/Fr 426 Poa palustris Se/Fr 35 Potentilla anserina Se/Fr 3.760/4* Ranunculus repens Se/Fr 11 Ranunculus sceleratus Se/Fr 54 Experimental field with Hordeum vulgare, Ranunculus aquatilis agg. Se/Fr 16 Camelina sativa, Linum usitatissimum and Vicia Schoenoplectus cf. lacustris Se/Fr 202 faba in front of the dike at Cappelersiel 1961 Schoenop. cf. tabernaemontani Se/Fr 3/3* Camelina sativa (gold-of-pleasure) is known Sphagnum spec. Leaflet 5.448 as a former weed in fields of flax, showing Trifolium fragiferum Cal 13 some co-evolution. In the Clay District it Typha spec. Se/Fr 561 was cultivated separately at least since the * charred late Bronze Age. At the late Bronze Age Skl – sklerenchymatous spindles site Rodenkirchen-Hahnenknooper Mühle, Cal – calyx

34 The majority of species represents open A special find is a siliqua fragment of Isatis habitats like pastures and meadows, also tinctoria which we now have recorded at ruderals and weeds were found in partly three places in the Clay District, all dated to large quantities. the first centuries A.D., two in the area of the salt marshes (Sillens and Feddersen Pastures, meadows Wierde) and one in a settlement at the river Bromus hordeaceus/secalinus Se/Fr 16 bank of the river Hunte, a tributary to the Calluna vulgaris Se/Fr 16 river Weser. Most probably, Isatis has been Cynosurus cristatus Se/Fr 32 used for dying textiles and was imported or Festuca ovina/rubra Se/Fr 20 grown in gardens because it is unlikely that Filipendula ulmaria Se/Fr 98 it could grow in the Clay District with its Holcus lanatus Se/Fr 69 harsh ecological conditions. Hypericum perforatum Se/Fr 16 Juncus articulatus Se/Fr 64 Leontodon cf. autumnalis Se/Fr 108 Lychnis flos-cuculi Se/Fr 68 Poa pratensis/trivialis Se/Fr 3.411 Poa sp. Se/Fr 112 Potentilla erecta Se/Fr 13 Stachys palustris Se/Fr 10/2* Trifolium repens s. str. Flower 36 Trifolium sp. Se/Fr 210 Trifolium sp. Flower 4.552 Ruderals Chenopodium glaucum/rubrum Se/Fr 809 Elymus repens Se/Fr 214 Eupatorium cannabinum Se/Fr 16 Plantago major s.l. Se/Fr 2.126 Poa annua Se/Fr 185 Urtica dioica Se/Fr 18 Ruderals/weeds Agrostis sp. Se/Fr 31.976 Atriplex sp. Se/Fr 29 Isatis tinctoria, recent Brassica nigra Se/Fr 121 Capsella bursa-pastoris Se/Fr 16 Chenopodium album Se/Fr 493 Chenopodium sp. Se/Fr 256/1* Cirsium cf. arvense Se/Fr 31 Matricaria perforata Se/Fr 681 Polygonum aviculare agg. Se/Fr 416 Polygonum lapathifolium agg. Se/Fr 153/1* Solanum nigrum Se/Fr 297 Sonchus oleraceus Se/Fr 17 Urtica urens Se/Fr 44

* charred Siliqua fragments of Isatis tinctoria (near Elsfleth at the river Hunte)

35 Literature:

BRANDT, K., 1984: Der Fund eines mittelalterlichen SCHMID, P., 1988: Die mittelalterliche Neubesiedlung Siels bei Stollhammer Ahndeich, Gem. Butja- der niedersächsischen Marsch. In: Bierma, M., dingen, Kr. Wesermarsch, und seine Bedeutung Harsema, O. u. van Zeist, W. (Hrsg.): Archeologie für die Landschaftsentwicklung zwischen Jade- en Landschap, 133-165, Groningen. busen und Weser. Probleme der Küstenforschung im südlichen Nordseegebiet 15, 51–64.