Journal of Archaeological Science 1988,15,503-5 13

Late Atlantic and Early Subboreal Vegetational Development at Trundholm, Denmark

Else Kolstrup’

(Received 28 October 1988, revised manuscript accepted I8 March 1988)

Two pollen diagrams from Trundholm in northwestern Sealand (Denmark) are presented. The diagrams cover most of the Late Atlantic and almost all of the Early Subboreal periods. The locality is coastal and was influenced by Littorina sea-level changes. It was not possible to correlate shell layers recognized in borings on lithologi- cal grounds. It is further concluded that crop cultivation and probably also grazing by domesticated animals took place in the area during the Late Atlantic. In so far as the discontinuous records allow, it is tentatively suggested that the impact of human activity on the vegetation increased in three successive stages during Late Atlantic and Early Subboreal times.

Keywords: DENMARK, POLLEN ANALYSIS, ATLANTIC, SUBBOREAL, HUMAN IMPACT.

Introduction In‘preparation for the construction of a new road through Trnndholm-Mose, Denmark (Figure 1), E. M. Jacobsen made a large number of borings in the area. He discovered that it had been subject to a number of sea-level changes during Holocene time (Jacobsen, 1982, 1983). In order to see whether shell layers recognized from cores could be correlated from one part of the area to another, and in order to add precision to the chronology, palynological investigations were made. Samples were collected from three cores by E. M. Jacobsen in 1986. The distance between cores is approximately 400 m. In core 24 there were 3.65 m of sediment, including two shell layers. In core 36,3*80 m of material included one shell layer. The third deposit which was sandwiched between two shell layers was only about O-4 m thick, and it is not examined in the present paper.

According to Jacobsen, the surface of the area is between 2 and 3 m above the present sea level; at core 24 the soil surface is at 2.03 m, and in core 36 it is 2.82 m above present sea level. According to Milthers (1943), there was an open connection to the sea during the Littorina transgression, and the area may thus have formed a bay during (at least part of) the deposition of the investigated sediments.

During the palynological work, it became clear that the pollen sections were applicable not only to the question of correlating and dating cores and shell layers, but they could also be used for the unravelling of the interaction between human activity and vegetational development around the bay.

OMosevej 12, Blans, DK-6400 Ssnderborg, Denmark.

503 0305GUO3/88/050503 + 11 %03.00/O 0 1988 Academic Press Limited

504 E. KOLSTRUP

Figure I. Map of Denmark with insert map of part of northwestern Sealand. A tentative, generalized outline of the bay during the highest Littorina coastline is shown as are the locations of cores 24 (coordinates 55”3’2” N, 1 l”5’26” E) and 36 (W3’7” N, 1 l”5’6” E). Partly after Jacobsen (1982).

Sediments and Laboratory Methods The lithology indicated in the pollen diagrams is based on Jacobsen’s field descriptions and a description of 1 cm3 samples in the laboratory according to the method of Troels-Smith (1955). Since the descriptions of the series are to some extent based on the small samples for pollen analysis, it is possible that they are slightly biased toward higher organic content.

The sediments are as follows.

Core 24 0.40-O-90 m:

0*9&1.18 m: 1.18-1.40 m: 1.40-2.45 m: 2.45-3-70 m: 3.7G3.80 m: 3.80-4.10 m:

Ga3 Gsl Ld+. Green-grey, medium-size sand with thin layers of sandy gyttja. Ga3 Ldl. Grey-green sand and gyttja with thin sand layers and shells. Grey sand with shells. Ga2 Ld2. Grey-green, sandy gyttja with thin sand layers and shells. Ld4 Ag+. Green, silty gyttja with shells. Grey sand with shells. Ld4 Ga+. Green, fine sandy-silty gyttja with shells.

Core 36 2.45-2.80 m: Ld3 Gal. Greenish-grey sand with layers of gyttja, and shells, 2.80-3.60 m: Ld4 Ga+. Green, sandy gyttja with shells. 3.6Ck5.50 m: Ld4 Ag+. Green, silty and locally sandy gyttja with shells. 5-50-5.95 m: Grey sand, gravel and shells with plant fragments. 5.95-6.25 m: Ld4 Ag+. Green, silty gyttja with shells.

VEGETATIONAL DEVELOPMENT IN DENMARK 505

The preparation of the samples included treatment with HCl, sieving, KOH, Erdtman acetolysis and separation with ZnBr, with a specific gravity of 2.0. Finally, the pollen was stained with basic fuchsine and embedded in glycerine.

The slides contained little non-pollen material, and in most samples the pollen was well preserved. In core 24, the Tiliu curve is split into two. The high percentage is for the total of Tiliu pollen, whereas the black curve represents pollen that was well preserved. The difference is made up of grains of which the exine was thinned or pitted due to corrosion (cf. Aaby, 1983).

The calculation of the percentage is based upon a tree pollen sum including Corylus. In all samples, charcoal particles with a longest axis of c. 10 pm and more were counted. In the diagram, the curves are on the same horizontal scale except for charcoal.

Description and Zonation of the Diagram The regional zonation of the pollen diagrams is primarily based on the arboreal pollen types, and it is therefore mainly these types that are dealt with here. Various non-tree species will be integrated in the section on vegetational development and human activity.

Projle 24 (Figure 2) The lowest spectrum at 4.05 m contains a relatively high percentage of non-determinable pollen and spores. There is some Gramineae and Cyperaceae pollen as well as spores of Filicales. Tiliu pollen is around lo%, and most of this pollen is thinned and/or corroded. Various tree pollen types from deciduous trees are present. This spectrum may represent a mixture of material, possibly of redeposited and/or older oxidized material, and material deposited when the accumulation of organic material started at the site.

Between 3.99 and 3.33 m Alnus forms lO-20% of the pollen sum, gently increasing upwards towards the shell layer (I& Betula and Pinus values both have 5-10%; QuercuS has l&l 5% and is gently increasing upwards from the shell layer; Tiliu is usually between 5 and 15%, with a maximum just below and just above the shell layer; and Ulmus generally has percentages between 10 and 20%. Both Tiliu and Ulmus have gradually decreasing percentages from the shell layer and upwards. Corylus is present at 2&40%, and there is a general increase from the shell layer upwards. V&urn and Hederu are present throughout and Fraxinus is regularly found. At some levels, there are high percentages of charcoal fragments.

According to Mikkelsen (1949), the transition between Early and Late Atlantic is put where the Pinus curve decreases from 20% to about 10% and where there is an increase in Quercus. Berglund (1966) and Gaillard (1984) also note an increase in Quercus at this transition. According to Nilsson (1935), the Late Atlantic exhibits high values of Quercus, Ulmus, Tiliu and Corylus throughout. Furthermore, Fruxinus pollen is regularly found in the Late Atlantic, whereas it is sporadic in the Early Atlantic.

In the Trundholm diagram from core 24, the Quercus percentages are high from the start, Fruxinus is as well represented as later, and only in the (mixed?) pollen of the spectrum at 4.05 m is there a high Pinus percentage. Accordingly, the lower part of the diagram, up to 3.33 m, is attributed to the Late Atlantic-AT2.

The pollen composition is rather similar above and below the shell layer, but the Late Atlantic is characterized in many diagrams by rather constant percentage values of the various trees through this zone. In the absence of other dating evidence, it cannot there- fore be decided how long a period is represented by the gap between 3.69 m and 3.81 m; and since there is a possibility of erosion at 3.81 m when the shell layer was formed, sedimentation rates cannot be deduced from the pollen record.

Between 3.33 m and 3.27 m, there is a decrease in Ulmus from 15.5 to 3.4%. Since the percentages remain low above 3-27 m, the transition between Atlantic and Subboreal is

506 E. KOLSTRUP

placed between 3.33 and 3*30m. From that level to the top of the diagram, Alnus has values in the range 20-30%. Bet& has a maximum representation of lO-15% between 3.24 and 2.8 1 m, after which the values remain between 5 and 10%. There are single finds of Fugus and Curpinus up to 064 m, but above that both curves become continuous with values below 1 Oh. Fruxinus becomes more frequent around 2.5 m and has high percentages above the upper shell layer (II&. The values for Pinus remain almost constant throughout, whereas those for Quercus become higher above II,,. Generally speaking, Tiliu and Ulmus both have gently decreasing percentages from 3.27 up to 245 m, whereafter they gradually increase again until just below the upper shell layer. Above the shell layer, the percentages of Tiliu decrease again. Various herbs and other non-tree species are found throughout the zone, and at some levels there is much charcoal. From 2.39 m upwards, there is an almost continuous presence of Ruppiu, and above the shell layer its percentages are high.

In diagrams from Prresto Fjord (Mikkelsen, 1949) and south Sweden (e.g. Nilsson, 1935,1961; Gaillard, 1984), the transition between Early and Late Subboreal is character- ized by a decrease involving at least some of Quercus, Fruxinus and Tilia, and there are continuous curves for Fugus and Carpinus with values of around or more than 1% from the transition upwards. In the Trundholm diagram, none of these criteria are satisfied. But Fagus and Carpinus do have continuous curves, and probably the upper part of this diagram belongs to the latest part of the Early Subboreal and is conceivably very close to the transition between the Early and Late Subboreal.

Profile 36 (Figure 3) Below the shell layer, I,,, Pinus has values of around 5% and the percentage of Quercus is about lo%, a value which the taxon retains above the shell layer. The Alnus and Tiliu percentages are as high as above the shell layer, Ulmus and Corylus are slightly lower, and Fraxinus is sporadic. Using this evidence in the comparison with other diagrams, a Late Atlantic age is proposed for the lower part of the core. Between 3.38 and 3-3 1 m, the Ulmus percentage decreases and remains low from that level. Therefore, the transition between Atlantic and Subboreal is placed here.

Between 4.74 and 4.41 m, there are lower percentages of Tilia mirrored by higher percentages of Corylus. From the level between 4.41 and 4.29 m up to the end of the zone, there are, generally speaking, gently increasing values of Alnus, Quercus and Corylus, and decreasing amounts of Pinus, Tiliu and Ulmus. In the spectrum at 3.64 m, however, there are low percentages of Tiliu and Ulmus coinciding with higher values of Quercus. Between 4.41 and 3.80 m, there are high percentages of charcoal particles.

Above 3.3 1 m, there are generally increasing values of Alnus and Be&la, whereas Pinus, Quercus, Tiliu, Ulmus and Corylus exhibit only small fluctuations. Carpinus and Fagus are absent. Consequently, it is concluded that this part of the diagram belongs to the Early Subboreal.

Stratigraphic Relationship between the Tnmdholm Cores 24 and 36 In the above descriptions and zonations, it was concluded that (part of) the Late Atlantic and (part of) the Early Subboreal is present in both diagrams. In both cores, there is a shell layer below the elm decline, and in core 24 there is one above it (Figure 4). In the uppermost spectrum of core 36, the Tilia and Ulmus values are unchanged as compared to the spectra between 2.8 1 and 3-20 m. Betula has decreased, Carpinus and Fugus are absent, and Fruxinus is scarce. Ruppia does not yet form a continuous curve, Humulus and Rumex are present and Plantugo lunceoluta is well represented. A comparison with core 24 between 2 and 3 m leads to the suggestion that the spectrum at 2.45 m in core 36 fits somewhere between 2.40 and 2.75 m in core 24.

10

2c

3c

4C

Trundholm 24

io5 511

i26 5’0 05 506

524 466

t- . .

-a

t

I I I

t . . . . , 0 50%

Figure 2. Pollen diagram from Trundholm core 24.

Trundholm 36

506

507

523

561 523

512 54

529 523

515

505 504 607 565 522

529 515

595 563

669 635 520

567

503 516

599 524 605 518 508

517 524 537

.

t . . . . I 0 50%

+

c-

*-

*

c-

+

Figure 3. Pollen diagram from Trundholm core 36.

, , ,-, , , , , .-. . , , .-. . . , . . 0 50% E.K. 1.. ..,

VEGETATIONAL DEVELOPMENT IN DENMARK 507

Depth Depth below related soil to sea surface level

m m 0 +2.03

1 0.40 +1.63

t

1124

Depth Depth below related soil to sea su tface level

m m 0 +2.82

2.45 +0.37

0

5.42 -2.60

136

6.05 -3.23 6.24 -3.42

Figure 4. Pollen stratigraphic integration of cores 24 (left) and 36 (right) from Trundholm.

-0.53

Below the elm decline, there are parallel trends in the two diagrams for Alnus, Pinus, Quercus, Tilia, Ulmus and Corylus, and the respective percentages of these are comparable at the various levels. It is therefore suggested that the pollen picture in core 24 between the top of I,, and the elm decline parallels the section between 4.29 and 3.35 m in core 36. It is not possible to find a convincing relationship between the lower part of I,, with core 36 or of I,, with the lower part of the diagram from core 24.

Vegetational Development and Human Activity The former influence of human activity on the vegetation is usually partly deduced from the presence of various indicator plants (e.g. Behre, 1981). The presence of Triticum type pollen, for example, shows that a Triticum type crop must have been grown. The presence of Hordeum type pollen, on the other hand, may equally well represent the former presence of the wild grasses such as Elymus arenarius. It is therefore important that the grass pollen

508 E. KOLSTRUP

types are distinguished as far as possible. But even with good microscopical equipment, certainty to specific level is usually difficult to obtain, and the determinations in the present paper should consequently be regarded as being “best fits”. For the determinations, the size criteria in Beug (1961) are used for cereal types, i.e. maximum diameter of the pollen grains is > 37 urn, the pore diameter is > 2.7 urn, the width of the annulus > 2.7 urn and the thickness (height) of the annulus more than 2.0 urn. Apart from the dimensions, also the surface structures of the grains (isolated dots-Hordeum type, groups of (2)3-6 dots- Triticum type) as shown in Beug’s figures and descriptions, are used for distinguishing between the types.

Another indicator that is regarded as probable evidence of human activity is Plantago lanceolata which occurs both in meadows and pastures, preferably in meadows with an open vegetation structure (for further particulars, see Groenman-van Waateringe, 1986). Other types are also useful (cf. Behre, 198 1). There are, however, two problems which need further elaboration. One is how to distinguish the influences of pastures from those of arable land. The other is of importance to the interpretation of near-coast cores such as the present ones from Trundholm, where the possible activities of human beings and animals took place at some unknown distance from the site of pollen deposition, and where changes in sea level could foster the growth of maritime vegetational elements that are frequently associated with human activity in inland localities. As a consequence of these uncertainties, it has been decided not to group various pollen types “ecologically” into curves that might possibly give an erroneous picture of human influence. Instead, a curve of the total percentages of dry-land non-arboreal pollen in each spectrum is given to the right-hand part of the diagrams.

In the following outline of the vegetational development, the data of the two cores are integrated and used for the reconstruction. In both pollen diagrams, deciduous forest taxa are fully established from the start. Light demanding trees and shrubs are few, and field- stratum vegetation is represented by fern spores in the lower part of core 36. In the lower part of core 24, and after the deposition of the shell layer in core 36, there is representation of Calluna, Poaceae, Artemisia, Chenopodiaceae and Filicales, as well as Pteridium. This pollen composition might point to the former presence of a shore area with low herb communities surrounded by forest.

In core 24 there is a Poaceae pollen grain with a diameter of 53 urn which is most probably of the Triticum type, and high charcoal percentages at 3-93 m; Plantago lanceolata occurs at 3.84 m; and P. major/media at 3.90 m. Furthermore, a pollen grain, 58 urn in diameter, of Hordeum type was found (NB the embedding medium is glycerine, and it is probable that swelling of the pollen grains has occurred). Accordingly, it is postulated that some type of Triticum was cultivated, and the Hordeum type pollen may also represent a cultivated species, but could also be a wild grass type.

In southwest Sweden, imprints of Hordeum, Triticum monococcum and T. compactum seeds are found in Ertebslle pottery (Jennbert, 1984) so possibly the same types were cultivated in Sealand. Since the indicators of human activity are found below the shell layer I,, (which is below the elm decline) they are indisputably older than the elm decline. This is consistent with findings from 8, mosen in Denmark. In an unpublished thesis, Stockmarr (1966) reports the presence of Triticum pollen in samples 17, 16 and 15 (determination by J. Stockmarr and Sv. Jorgensen) together with high percentages of Urtica pollen and of charcoal fragments. The elm decline in his diagram is at a higher level (between samples 12 and 1 l), and Stockmarr concludes that there was agriculture and some opening up of the forest from around 5350 years BP in the Amosen area. In the Trundholm locality, it cannot be stated how old the early cereal type finds are, but they were deposited some time before the sediments in core 36 at levels of about 4.30 m and upwards were laid down (cf. Figure 4).

VEGETATIONAL DEVELOPMENT IN DENMARK 509

In core 36, there is a maximum of charcoal between 3.75 and 4.45 m, and at 4.05 m there is a pollen grain of P. lanceolata. Furthermore, there is the presence of cereal pollen types/Hordeum type, and at 3.38 m there is a Lychnis type and Polygonum aviculare. These elements taken separately are not necessarily proof of human activity (cf. Behre, 1981; Groenman-van Waateringe, 1983), but taken together they strongly suggest that there was cultivation of the land when this part of the core was deposited, i.e. after the time of the Triticum type pollen from core 24 was deposited and before the elm decline.

The sum of dry non-arboreal pollen percentages is between 5 and 20 throughout, except for the lowermost parts of the diagrams and above the upper shell layer in core 24 where it is relatively high. There are small fluctuations and maxima of the curves both below and above the elm decline, but there is no evidence in the pollen diagrams to suggest that the elm decline meant an opening of the forest and subsequent immigration of herbs and grasses, or that some sudden opening up of the forest took place shortly before or after that time. From the resolved diagrams, it can be seen that the grass percentages are low when compared with those of sandy arable land in the Netherlands (cf. Groenman-van Waateringe, 1986) and if the values from Trundholm represent the amount of grass in the area as such, grazing animals could hardly have survived during Late Atlantic and early Early Subboreal time. It is possible that there were no pastures at this time in Trundholm. Yet a mixed deciduous forest on the moraines in Sealand may have been able to regenerate more quickly after use than forest on the sandy Dutch soils, and pollen of plants from the undergrowth, e.g. Poaceae, may consequently be relatively poorly represented in the Trundholm diagram as compared to the Dutch finds. Besides, Jennbert (1984) reports findings of bones of cattle (Bos taurus) and domesticated swine of pre-elm decline age in southern Sweden. It therefore seems likely that these domesticated animals were also present in Sealand. If one envisages the environment at this time as a whole, grazing animals may not have preferred the coastal area where the water was salt or brackish, but may have grazed further inland where there was fresh water-with a wooded area between their pastures and the sea.

The gradual decrease in the pollen percentages of Ulmus and Tilia (the pollen of which could more easily reach the bay) during the upper part of the Late Atlantic might well be the result of use of these trees for fodder as has been suggested for other areas (e.g. Giiransson, 1986; also cf. Troels-Smith, 1953,196O). In diagram 36, there is a minimum of Tilia and Ulmus at 3.64 m. It cannot be decided whether this is due to human influence, reworking of sediment or some other factor.

Generally speaking, it is suggested that in the Trundholm diagrams the Late Atlantic human influence on the surrounding vegetation is detectable. In many other diagrams (e.g. Iversen, 1941, 1973; Mikkelsen, 1949; Troels-Smith, 1953; Berglund, 1966) it is not; or rather, there is no direct evidence from which to decide whether there was crop culti- vation at that time. One explanation for this difference could be that most pollen diagrams are from lakes and bogs which had a surrounding cover of forest and shrub, and that the indicator species could not easily spread from woodland openings into the lakes and bogs (Tauber, 1977). An additional explanation might be that the Late Atlantic peoples under- stood their environment and adapted themselves to it with some, but minimal damage to it, as is the case with native peoples in parts of the tropical rain forest today.

The transition to the Early Subboreal marked by the elm decline, and in core 36 also by a decline of Tilia, is easily recognized in both diagrams, and the reduction of the elm percentage must have taken place rather suddenly. According to some authors (e.g. Huntley & Birks, 1983; Moore, 1984; see also the discussion in Nilsson, 1964), the elm decline took place around 5 150 BP within a fairly short time span in northwestern Europe. If that was indeed the case, the most likely explanation for it in an area where crop cultivation was already present and where domesticated animals were probably present as

510 E. KOLSTRUP

well would be an attack by elm disease (see the discussions on the causes for the elm decline by, for example, Iversen, 1973; Huntley & Birks, 1983; Perry & Moore, 1987), which in particular would affect girdled, and therefore weakened, trees (cf., e.g., Giiransson, 1986). Besides, it is known that elm bark beetles were present and active around the time of the elm decline in northwestern Europe. On Hampstead Heath (England), Girling & Greig (1985) found wing cases of Scolytus scolytus a few centimetres below the elm decline, and in Amosen (Denmark) a piece of elm wood with a gallery system made by the elm bark beetle S. luevis Chap. was found at “the critical level” (Fredskild, 1968; determination by B. Bejer-Petersen in Stockmarr, 1966).

The theory of elm disease might be supported by the present diagram in which there is no evidence of intensified husbandry just after the elm decline, but of course continued use of elm may have prevented it from regaining its former importance. In core 24, there is continued reduction of the percentages of Ulmus and Tilia, and the same crops and weeds seem to be present. There is no increase of charcoal percentages, but there is an increase of Bet& and Alnw frequencies which suggests that these not particularly useful trees were allowed to spread into some of the areas where were probably previously occupied by Ulmus and Tilia. Instead of Tilia and Ulmus, Quercus trees had, without necessarily becoming more numerous, come to dominate the pollen record for the taller trees. The increase of Alnus could indicate moister soil conditions and may be supported by the sea- level curve, but there is no support for that assumption from other plants.

From around 3 m, human impact becomes clearer in profile 24, and from 2.93 m it further intensifies. Plantago lanceolata and P. major/media point to increased cultivation and grazing. Triticum type and probably also Hordeum were grown, The regular represen- tation of Humulus here could mean that it was cultivated too. At about the same time, Urtica and Rumex seem to have been frequent “weeds”. Yet the activities of the inhabi- tants and their animals do not seem to have appreciably influenced the pollen percentages of Poaceae, Cyperaceae, Artemisia and Chenopodiaceae. On the other hand, Tilia and Ulmus retain very low percentages, and it is possible that grazing grounds and the inhabited areas were the potential growing areas for these trees, and that the leaves of the remaining trees were still used as fodder.

Pollen grains from fresh-water plants are so relatively few here that their presence might be explained as having been brought into the locality by brooklets from land. From 2.39 m, Ruppiu must have grown at or near the coring site. This indicates brackish or salt, shallow, quiet water conditions. Possibly Spirogyra can be taken as an indication for brackish water also (van Geel, 1976). From 1.72 m in core 24, Ulmus and Tiliu became more frequent. The increase is recognized in many pollen diagrams, and in southwestern Sweden it is dated to c. 4500 BP (Berglund, 1969; Goransson, 1986). After shell layer II,, was deposited, the environment changed. Fruxinus, a relatively poor pollen producer (Andersen, 1970), is responsible for up to 8% of the tree pollen. The forest was probably still dominated by Quercus, while Ulmus and Tilia may have existed mainly as stands of trees girdled for fodder. The wetter areas were occupi,ed by Alnus. Corylus was still an important component of the forest, and by now single Curpinus and Fagus trees were probably present. Some herbs attain relatively high percentages-Poaceae, Artemisia, Chenopodiaceae, Plantago types, Rumex and Urtica. Various cereals are well represented and human impact on the environment had probably become stronger while in the bay the conditions for Ruppia had improved.

Human Impact before the Elm Decline in Trundholm as Compared to other Areas

The possibility that there was Late Atlantic crop cultivation in northwestern Europe is becoming increasingly demonstrated in palaeobotanical records. In southern Sweden,

VEGETATIONAL DEVELOPMENT IN DENMARK 511

there are reports of cereal type pollen from three localities, namely FBrarp (H. Hjelmroos, in preparation), Bjarsjiiholmsjiin (Nilsson, 1961) and Dags Mosse (Goransson, 1983, 1986). Also in Belgium, cereal pollen is present below the elm decline (e.g. Beyens, 1984) as it is the case in Ireland (summary by Groenman-van Waateringe, 1983) and a summary by Edwards & Hirons (1984) of cereal pollen finds in Ireland and Britain mentions the presence of both Triticum and Hot&urn types. From Denmark, Stockmarr’s unpublished, well documented, but almost for

R otten 1966 results show that Triticum was grown some

time before the elm decline in mosen in western Sealand. Additional evidence is the archaeological study of imprints in Ertebslle pottery from Ldddesborg near Malmo in southwestern Sweden by. Jennbert (1984) (see above). The finding of Triticum type, Hordeum type and Plantago pollen in Trundholm thus fits in well with the findings from other parts of northwestern Europe.

It is generally known that transport of pollen from clearings in forests to other localities is very limited (Tauber, 1977), and it has been stressed that plants with a pollen dispersal as poor as that of wheat and barley are poorly represented at some distance from the growing site (Behre, 1981; Groenman-van Waateringe, 1983). In more open, near-coast sites such as Trundholm the conditions for dispersal and deposition of pollen may have been more favourable than in localities further inland. Besides, people may have used the bay for a swim to wash off the dust after a day’s work with the crops. On the basis of the above, seen together with the findings from other areas, it is hard to reject the theory that people cultivated crops and kept domesticated animals during Late Atlantic time in north- western Europe. How one should envisage the vegetation in detail at that time still leaves much to the imagination, but the idea of using Ulmus and Tilia for fodder would be a good explanation for the trend of these curves in Trundholm.

In many parts of the diagrams, there are charcoal percentages with values of between 10 and 40%. These low values may reflect the daily use of fire. At some levels, the charcoal values are higher, suggesting that there was burning in excess of the daily fires. Uncon- trolled fires are always possible, but it is also conceivable that small areas, possibly between trees as suggested by Gijransson (1986) were cleared by fire in order to be used for crop cultivation. Finally, there is a possibility that charcoal is occasionally brought into the site by chance under specific wind and water conditions.

Conclusions The two pollen diagrams from Trundholm cover most of the Late Atlantic and almost all of the Early Subboreal. The presence of Ruppia in the sediments indicate that there was marine and brackish influence during the Littorina transgression in the Trundholm area, and the investigation has shown that on the basis of lithostratigraphy, it is not possible to correlate shell layers recognized in borings over distances of about 400m. It was not possible to precisise the ages of the shell layers within the late Atlantic on palynological grounds, as has been done in western Skdne (Digerfeldt, 1975).

The palynological records further show that the deepest organic material in the cores was deposited after the mixed deciduous forest had become fully established in the area. The diagrams show that there was crop cultivation and furthermore point to feeding of domesticated animals in that area for some time before the elm decline.

Three main phases of vegetational development are inferred. The first starts with the presence of Triticum type and Plantago lanceolata pollen well below the elm decline, and there are moderate influences on Ulmus and Tilia, the pollen percentages of which gradu- ally become reduced. This phase may have persisted until some time after the elm decline because there are no indications of increased human activity in the records around and immediately after the decrease of Ulmus. If the elm decline was contemporaneous in

512 E. KOLSTRUP

northwestern Europe, the interpretation of it as being the result of disease helped by human activities (cf. Giiransson, 1986) seems likely. In other words, the records suggest that the elmdecline was not solely caused by people, and it does not seem to have had any immediate, major impact on their way of living either. But it seems likely that girdling of stands of elms could make them more vulnerable to disease than healthy trees were, and by continuing to use the elm the tree may have been prevented from regaining its old terrain.

The second phase of the development starts at around 3.12 m deep in core 24, where the increased amount of cereals, grasses, Plantago and Rumex together with low Ulmus ‘and Tilia percentages point to slightly increased human activity. During the third phase which is above the upper shell layer in core 24, the impact has further intensified.

Acknowledgements I am very grateful to E. M. Jacobsen (Geokon, Copenhagen) for his initiative to have the deposits in Trundholm palynologically dated; to B. van Gee1 (University of Amsterdam), W. Groenman-van Waateringe (I.P.P., Amsterdam) and I. Sorensen (Zoological Museum, Copenhagen) who provided valuable comments on an earlier manuscript; and to A. Yde-Andersen (Statens Forstlige Forssgsvzsen, Copenhagen) and B. Bejer-Petersen (Kgl. Veterimer- og Landbohojskole, Copenhagen), for information on Scolytus species and Dutch elm disease. K. J. Edwards (University of Birmingham, U.K.) kindly corrected the English text. The major part of the investigation was funded by the Carl&erg Foundation. I am most grateful to Jens Stockmarr who generously gave me a copy of his unpublished thesis together with permission to use it as I wished.

References Aaby, B. (1983). Forest development, soil genesis and human activity illustrated by pollen and

hypha analysis of two neighbouring podzols in Draved Forest, Denmark. Danmarks geologiske Undersogelse II, 114, 114.

Andersen, S. T. (1970). The relative pollen productivity and pollen representation of North European trees, and correction factors for tree pollen spectra. Danmarks geologiske Undersogelse II, 96,99.

Behre, K.-E. (198 1). The interpretation of anthropogenic indicators in pollen diagrams. Pollen et Spores 23(2), 2255245.

Berglund, B. E. (1966). Late-Quaternary vegetation in eastern Blekinge, southeastern Sweden. II. Post-Glacial Times. Opera Botunica 12(2), 182.

Berglund, B. E. (1969). Vegetation and human influence in South Scandinavia during Prehistoric time. Oikos (Suppl.) 12,9-28.

Beug, H.-J. (1961). Leitfaden der Pollenbestimmungfiir Mitteleuropa und angrenzende Gebiete. Stuttgart: Gustav Fischer, p. 63.

Beyens, L. (1984). Palynological and radiometric evidence for an early start of the Neolithic in the Belgian Campine. Notae Praehistoricae 4,89-95.

Digerfeldt, G. (1975). A standard profile for Littorina transgressions in western Sk&e, South Sweden. Boreas 4,125142.

Edwards, K. J. & Hirons, K. R. (1984). Cereal pollen grains in pre-elm decline deposits: implications for the earliest agriculture in Britain and Ireland. Journal of Archaeological Science 11,71-80.

Fredskild, B. (1968). Det abne lands opstaen. Vort abne land. Danmarks Naturfredningsforenings Arsskrift 1968, pp. 9-15.

Gaillard, M.-J. (1984). A palaeohydrological study of Krageholmssjon (Scania, South Sweden). Lundqua Report 25,40.

Geel, B. van (1976). Fossil spores of Zygnemataceae (The Netherlands). Review of Pulueobotuny and Palynology 22,337-344.

VEGETATIONAL DEVELOPMENT IN DENMARK 513

Girding, M. A. & Greig, J. (1985). A first fossil record for Scolytus scolytus (F.) (elm bark beetle): its occurrence in elm decline deposits from London and the implications for Neolithic elm disease. Journal of Archaeological Science 12,347-351.

Groenman-van Waateringe, W. (1983). The early agricultural utilization of the Irish landscape: the last word on the elm decline? In (T. Reeves-Smyth & F. Hamond, Eds) Lam&ape Archaeology in Ireland. British Archaeological Reports (BAR) British Series 116, pp.217-232.

Groenman-van Waateringe, W. (1986). Grazing possibilities in the Neolithic of the Netherlands based on palynological data. In (K.-E. Behre, Ed.) Anthropogenic Indicators in Pollen Diagrams. Rotterdam: Balkema, pp. 187-202.

Goransson, H. (1983). Nar b&jar neolitikum? Popular Arkeologi 1,3,4-7. Goransson, H. (1986). Man and the forests of Nemoral broad-leafed trees during the Stone Age.

Striae 24, 143-152. Huntley, B. 8t Birks, H. J. B. (1983). An Atlas of Past and Present Pollen Maps for Europe:

O-13.000 Years Ago. Cambridge: Cambridge University Press, pp. 411-415. Iversen, J. (1941). Landnam i Danmarks Stenalder. Danmarks geologiske Undersogelse II, 66,68. Iversen, J. (1973). The development of Denmark’s nature since the Last Glacial. Danmarks

geologiske Undersogelse V, 7-C, 126. Jacobsen, E. M. (1982). Litorinatransgressioner i Trundholm mose, NV-Sjalland, en forelebig

undersogelse. Dansk geologisk Forenings Arsskrift for 1981, pp. 109-l 17. Jacobsen, E. M. (1983). Litorinatransgressioner i Trundholm mose, NV-Sjrelland, supplerende

undersegelse. Dansk geologisk Forenings Arsskriftfor 1982, pp. 5965. Jennbert, K. (1984). Den produktiva g&an. Acta Archaeologica Lundensia, Series IN 4,16,206. Mikkelsen, V. M. (1949). Praesto Fjord. Dansk Botanisk Arkiv 13,5, 171. Milthers, V. (1943). Nordvestsjaellands Geologi. Danmarks geologiske Undersogelse V, 6, 185. Moore, P. D. (1984). Hampstead Heath clue to historical decline of elms. Nature 312,8 Nov., 103. Nilsson, T. (1935). Die pollenanalytische Zonengliederung der spat- und postglazialen Bildungen

Schonens. Geologiska Fiireningens i Stockholm Fiirhandlinar 57,385-562. Nilsson, T. (196J). Ein neues Standardpollendiagramm aus Bjarsjoholmssjon in Schonen. Lunds

Universitets Arsskrtft. N.F. 2,56, 18,34. Nilsson, T. (1964). Standardpollendiagramme und C-14 Datierungen aus dem Agerods Mosse im

mittleren Schonen. Lunds Universitets Arsskrtft N.F. 2,59,7,52. Perry, I. & Moore, P. D. (1987). Dutch elm disease as an analogue of Neolithic elm decline.

Nature 326,5 March, 72-73. Stockmarr, J. (1966). Unpublished Thesis. Przstelyngen. Nationalmuseets 8, Afdeling,

Ksbenhavn, p. 34. Tauber, H. (1977). Investigations of aerial pollen transport in a forested area. Dansk Botanisk

Arkiv32, 1, 121. Troels-Smith, J. (1953). Ertebollekultur-Bondeskultur. Resultater af de sidste 10 Aars

Undersogelser i Aamosen. Aarbog for mordisk Oldkyndighed og Historie, pp. 5562. Troels-Smith, J. (1955). Karakterisering af lose jordarter. Danmarks geofogiske Undersogelse IV,

3, 10,73. Troels-Smith, J. (1960). Ivy, mistletoe and elm. Climatic indicators-fodder plants. Danmarks

geologiske Undersogelse IV, 4,4,32.