Extensive forest grazing and hay-making on mires – vegetation changes in south-central Sweden due to land use since Medieval times

The influence of pre-industrial animal husbandry on the boreal forest in south-central Sweden has been studied by pollen and charcoal analyses of peat profiles from two mires in the vicinity of a shieling site. The impact of farming on the local vegetation development is demonstrated from cal. A. D. 1300–1500 in three ways: forest clearance and cultivation of cereals at the local shieling site; alterations of hydrology and vegetation, such as an increase in Cyperaceae, at mires used for hay production; changes in the composition in the surrounding forest, with decreasing proportions of Betula, Picea and boreo-nemoral broadleaved trees and a consequent increase in Pinus, due to grazing and a change of fire regime. Similar alterations to the forest vegetation are noted at other sites in central and northern Sweden during the last thousand years, when the system of using shielings became more widespread. Hence, early animal husbandry is demonstrated to have had a regional impact on the long-term boreal forest development, replacing the original mixed deciduous-coniferous forest with Pinus dominated forest. Received November 27, 2001 / Accepted June 20, 2002 Correspondence to: Marie Emanuelsson     

Tracing and interpreting fine-scale human impact in northern Fennoscandia with the aid of modern pollen analogues

A set of moss samples (n=58) was collected and analysed to obtain modern pollen analogues for both natural and human induced vegetation types in northern Fennoscandia. Vegetation types with settlement, trampling and grazing were selected from the different latitudinal forest zones (birch, pine, and mixed forest). The moss species varied between samples but the size of the sample was kept constant. Numerical analyses such as Redundancy Analysis (RDA) indicate that in northern areas human presence is mainly visible as increased values of Gramineae, Rumex acetosa/acetosella, R. obtusifolius, Solidago-type and Achillea-type pollen. Partial RDA further reveals that settlement is strongly correlated with high values of Rumex acetosa/acetosella, whereas trampled sites are significantly characterised by Gramineae and, to a smaller extent, Cyperaceae pollen. It is therefore possible to distinguish the impact of different types of human activities on vegetation on the basis of the pollen spectra. Later, these data will be used to interpret the presence, nature, and duration of human impact from fossil records from the same area. Received June 6, 2001 / Accepted December 12, 2001     

Biostratigraphy and <Superscript>14</Superscript>C dating of a lake sediment sequence on the north-west Estonian carbonaceous plateau,interpreted in terms of human impact in the surroundings

The sediment stratigraphy of a medium-sized mixotrophic lake (Ruila) situated below the highest shoreline of the Baltic Ice Lake in the West-Estonian Lowland is described. The lake is without natural inlets our outlets. The reconstruction of vegetation and land-use history based on pollen data, combined with available archaeological data and detailed ¹⁴C dating allows us to give a provisional reconstruction of the temporal and spatial pattern of natural and human induced environmental changes in north-west Estonia during the Holocene. Both radiocarbon dates derived from terrestrial macrofossil dating by accelerator mass spectrometry (AMS) and conventional dating of bulk lake sediment are discussed. The isolation of the lake basin from the Yoldia Sea took place ca. 9700 cal B. C. The Ancylus Lake transgression at ca. 8400 cal B. C. did not reach the basin, but caused a ground water rise, seen in the sediment stratigraphy of the lake. The first signs of human impact on the pollen record appear ca. 5400 cal B. C. (Late Mesolithic). The history of arable farming has been divided into three periods: 1) introduction of crop cultivation and animal husbandry (1500 cal B. C. – A. D. 500); 2) establishment of animal husbandry A. D. 500–1000) and 3) establishment of crop cultivation and intensive cattle breeding (A. D. 1000–today). Due to unfavourable eda-phic conditions the introduction of arable farming was delayed for more than 1000 years compared with elsewhere on the north coast of Esotnia, and intensity of land-use never reached the same proportion as in these areas. Received August 15, 2001 / Accepted August 5, 2002 Correspondence to: Leili Saarse     

Data on mid-Holocene climatic, vegetation and anthropogenic interactions at Stanshiel Rig, southern Scotland

Pollen, microscopic charcoal and peat humification analyses were applied to radiocarbon-dated peat cores to examine environmental change before and after the mid-Holocene transition from hunter-gatherer (Mesolithic) to agricultural (Neolithic) communities in presently marginal upland pasture at Stanshiel Rig, Annandale, southern Scotland. The Mesolithic-Neolithic transition in northern Britain is characterised by a number kf key environmental changes as well as economic shifts, including temporal patterns of fire and the Ulmus decline. Deliberate vegetation modification by Mesolithic communities is not demonstrable at Stanshiel Rig, and openings in the woodland canopy may have been promoted by grazing by wild animals or have been a consequence of climate change. Changes in fire frequency are also correlated with peat- and pollen-stratigraphic evidence for shifts to a drier climate in the late Mesolithic, probably mediated through pedological and biomass-storage change. A single Ulmus decline occurred between ca. 5650 and 5600 cal B. P., and is related here to climate change. Neolithic-age impacts on the woodland were limited, and no cereal-type pollen were found. The difference between hunter-gatherer and opportunistic farmer/hunter-gatherer at this locally is argued to be insignificant, or not detectable palynologically. Received October 4, 2001 / Accepted July 22, 2002 Correspondence to: S. M. Cayless     

The long history of Cannabis and its cultivation by the Romans in central Italy, shown by pollen records from Lago Albano and Lago di Nemi

The cores from the Albano and Nemi lakes, near Rome, were studied within the European Union funded PALICLAS project and provided high resolution records of the Late-glacial and Holocene. Pollen evidence of increasing human influence on vegetation was recorded in the Holocene parts of both diagrams, and the Cannabis (hemp) curve was one of the major signs. In this paper we present unambiguous pollen evidence from the Cannabaceae records for the cultivation of hemp in central Italy by the Romans. The oldest records of Cannabis and Humulus (hop) date from to the Late-glacial. Hop pollen values rise during the mid Holocene, while hemp pollen becomes more abundant from ca. 3000 cal B.P. onwards. The highest earliest hemp peak (21%) is dated to the 1st century A.D. This ‘Cannabis phase’, with the abrupt rise of hemp pollen soon after the rise of cultivated trees (Castanea, Juglans and Olea) is associated with the increase in cereals and ruderal plants. This unambiguous proof of cultivation by Romans around 2000 B.P. occurs as well as a long lasting pre-Roman presence of hemp in the area, which is natural and possibly also anthropogenic. Subsequent clear episodes of cultivation in the medieval period were found. Received February 4, 2002 / Accepted September 13, 2002 Correspondence to: Anna Maria Mercuri, e-mail: mercuri.annamaria@unimo.it     

Multi-disciplinary evidence of the Holocene history of a cultivated floodplain area in the wetlands of northern Colombia

An environmental reconstruction of the last 10,000 ¹⁴C years of a frequently flooded wetland ecosystem in the lower Magdalena valley in northern Colombia is presented, on the basis of a multi-disciplinary study of the sediments of the upper 15 m of the core from Boquillas (74°33'E, 9°7'N; 20 m a. s. l.). We used the following studies: pollen, lithology, organic structures, clay mineralogy, soil and sediment geochemistry, and δ¹³C values. The chronology is based on 13 AMS radiocarbon dates; the humic acid fractions were used in the case of seven samples. Pollen from local origin (swamps, open grass-rich vegetation, and gallery forest) show the development of the wetland area. River-transported pollen from a greater distance (dry forest, montane forest, Alnus) show changes in river activity and reflect large-scale changes of climatic conditions in the Momposina basin. From c. 10,010 to 9370 uncal B. P. (zone BQS-Ia) the river system was of high energy, as inferred by the lithological changes. The landscape was dominated by open grass-rich vegetation with gallery forest along the streams. A marked representation of Alnus and montane forest taxa indicate significant water transport and river dynamics. Climatic conditions were dry. From c. 9370-8430 uncal B. P. (zone BQS-Ib) wetlands were isolated from the main river system, and clayey sediments with kaolinite, smectite and illite as the main minerals accumulated in a lower-energy environment. Climatic conditions were dry and changes in the seasonal precipitation favoured the expansion of the gallery forest. From c. 8430 to 8040 uncal B. P. (zone BQS-Ic) low values of river-transported pollen indicate dry climatic conditions and open vegetation became more abundant. The flooding frequency of the Boquillas site diminished. From 8040 to 4900 uncal B. P. (zone BQS-Id) the Boquillas site was dominated by open vegetation with patches of gallery forest along the streams. Supply of river-transported allochthonous pollen (from many sources) was minimal. Clay minerals from the sediments suggest variable temperature and precipitation. From c. 4900 to 1550 uncal B. P. )zone BQS-II) the site was within the reach of the main river system as is the case today. Frequent flooding, coinciding with peaks of river-transported grains of Alnus and high sediment supply, point to high precipitation in the composite catchment area of the Magdalena, Cauca, San Jorge, and Cesár rivers. High values of phosphorous in the upper part of the core point to the presence of a pre-Hispanic civilization, approximately from 2000 uncal B. P. onward. Construction of an extensive drainage system allowed irrigation as well as drainage depending the annual cycle of precipitation. The landscape was significantly modified and allowed an extensive crop production on a system of raised fields. Received May 18, 2001 / Accepted June 15, 2001     

Roman plant remains from Veli Brijun (island of Brioni), Croatia

41 archaeobotanical samples were analysed, which had been collected from the seabed at uvula Verige (Verige bay) on the island of Veli Brijun, Croatia, the site of a Roman villa which was settled from the 1st to the 5th century A. D. From the analysis of plant macrofos-sils it is evident that the eu-Mediterranean evergreen woodland, today described as Quercion ilicis in the phyto-sociological system, already existed in the Roman period. During this period it became degraded as a result of human activities to other vegetation types such as maquis and garrigue scrub, and grassland. The remains of Vitis vinifera (grapevine), Olea europaea (olive), Ficus carica (fig), and Pinus pinea (stone pine) were most frequently recorded; they all derive from very important and characteristic Mediterranean foods. Prunus avium (sweet cherry) and P. persica (peach), some vegetables and spices were probably cultivated, too, as well as some cereals, most probably Panicum miliaceum (millet). Juglans regia (walnut), Castanea sativa (sweet chestnut), and Corylus avellana (hazel) were possibly cultivated on the island or imported from neighbouring Istia. The records of some fresh water plants show that there was fresh water in uvala Verige and its surroundings in Roman times, much more than today. Received February 29, 2000 / Accepted January 31, 2001     

Late Quaternary environmental changes in the Lagoa da Curuça region (eastern Amazonia, Brazil) and evidence of Podocarpus in the Amazon lowland

Late-glacial and Holocene vegetational and climate dynamics and human impact of the eastern Amazon rain forest in the coastal region of eastern Pará State in northern Brazil have been studied in two sedimentary recores from Lagoa da Curu?a. Seven radiocarbon dates provide the chronology for two pollen and charcoal records starting from 11,700 and 9440 uncal B. P. to present. Dense and high diverse terra firme Amazon rain forest in the coastal area shows that there was no savanna during the Late-glacial period. The occurrence of Podocarpus trees in the coastal region during the Late-glacial indicate wet and markedly colder conditions at that time. A possible habitat for Pleistocene populations of Podocarpus trees which are now also evident from several other Amazon regions is discussed. There were no rain forest fires between 11,700 and 10,840 uncal B. P. The increase of charcoal particles in the lake deposits after this period suggest an early Amerindian occupation of the coastal region. Received March 26, 2001 / Accepted August 8, 2001     

Paleoenvironmental study of the Carquefou site (Massif Armoricain, France) from the end of the Sub-boreal

The town of Carquefou, some 10 km northeast of Nantes on the left bank of the river Erdre, occupies a site long associated with human activity. During road construction east of the town, ditches, enclosures and post holes characteristic of the late la Tène were discovered at the locality of “Le Clouet”, which led us to obtain core samples from a nearby peat bog. These investigations indicated the changes in vegetation since 3915±95 uncal B.P., [2828 (2459) 2074 cal B.C.]. The slopes in the surroundings of the bog have been relatively treeless since the Bronze Age, but a very open woodland vegetation composed of Tilia, Corylus and Quercus has been maintained until the present day. In the area around the bog, and Alnus wood with an undergrowth of Cyperaceae was the dominant vegetation, despite some changes probably related to human occupation since the Bronze Age. Beginning at 955±35 uncal B.P. [1004 (1036, 1144, 1146) 1181 cal A.D.], in the Middle Ages, the alders disappeared almost totally, apparently because of clearance or an increase in water level. Human presence led to intensified cultivation of different crops including Cannabis and especially Cerealia. Finally, the presence of a variety of anthropogenic indicator plants (Cichorioideae, Asteraceae, Plantago lanceolata, etc.) suggests that cattle were reared in the vicinity of the site. Received May 22, 2000 / Accepted March 29, 2001     

Vegetation dynamics of south-western Italy in the last 28 kyr inferred from pollen analysis of a Tyrrhenian Sea core

A continuous pollen record covering the last 28 kyr was obtained from core C106 collected in the Bay of Salerno in the southern Tyrrhenian Basin, seven radiocarbon dates and the recognition of two tephra layers (Y3 and Pompeii Pumice) providing good chronological constraints. The clear climatic signal given by the pollen spectra integrated by isotopic data, combined with comparisons with other Mediterranean sites, allowed the Last Glacial, Late Glacial and Holocene periods to be distinguished in the core. In particular, the Last Glacial period is characterised by large quantities of herbaceous and steppe elements such as Artemisia. The beginning of the Late Glacial has been correlated with the first increase of deciduous Quercus and the reduction of steppe and herbaceous elements. The Younger Dryas event is recorded only by oxygen isotopes while the vegetation does not seem to change, as in other Mediterranean sites. The Holocene corresponds to rich deciduous and evergreen forests. The first features which could be interpreted as signs of human presence are represented by a few grains of Juglans, Castanea and cereal-type while intensive olive cultivation and deforestation seem to fall within the Middle Ages. Received October 10, 2001 / Accepted June 20, 2002 Correspondence to: Elda Russo Ermolli     

Studies on the Holocene history of vegetation in the region of lake Srebarna (northeast Bulgaria)

The results of pollen analysis of two sediment cores from lake Srebarna (northeast Bulgaria) are presented. On the basis of the palynological data and the radiocarbon dates a reconstruction of the past flora and vegetation is made. For the first time a continuous palaeosuccession is established for the area of the Danubian Dobrudza and the Ludogorie district of northeast Bulgaria: a dominance of mixed xero- and mesophilous oak woods with Carpinus betulus, Ulmus, Tilia, Corylus during the Atlantic period; mixed oak woods with increasing importance of Tilia, Ulmus, Acer and a considerable presence of Carpinus betulus and Fagus during the Sub-boreal period; degradation of the woodland vegetation and transition to secondary plant communities with Carpinus orientalis and herbs during the Sub-atlantic period. Received January 5, 2001 / Accepted March 13, 2001     

Holocene vegetation and water level history in two bogs of the Cordillera de Talamanca, Costa Rica

Pollen records of Holocene sediment cores from the Costa Rican Cordillera de Talamanca (La Chonta bog, 2310 m and La Trinidad bog, 2700 m) show the postglacial development of the montane oak forest zone from ca. 9500 to 1500 yr BP. During the early Holocene (ca. 9500–700 yr BP), alder vegetation covered the La Chonta and La Trinidad bogs and their adjacent hills. The upper forest line is inferred to be at 2800–3000 m elevation. A Podocarpus-Quercus forest characterised the middle Holocene (ca. 7000–4500 yr BP). The upper forest line is located at >3000 m reaching the present-day altitudinal distribution. A Quercus forest characterised the late Holocene (ca. 4500–1500 yr BP). Compared to modern conditions, the early Holocene has similar average temperatures, but the moisture level was probably higher. Pollen evidence for the late Holocene indicates drier environmental conditions than today. In order to improve the paleoecological interpretation, we described the local vegetation and used moss samples as pollen traps at both montane bogs along strong soil moisture gradients.The Netherlands Centre for Geo-ecological Research, ICG     

Stone Age to recent land-use history at Pegrema, northern Lake Onega, Russian Karelia

The village of Pegrema in Karelia may be regarded as a Stone Age innovation centre in the large Lake Onega area. Two pollen and plant macrofossil diagrams are presented which represent the first contribution to the study of human impact in the area using anthropogenic pollen indicators. A continuous but sporadic human presence from the Mesolithic onwards is demonstrated. While there is no archaeological evidence relating to the period 4200–3000 B.P., the pollen data suggest continuous, though rather sparse human presence. The data do not support any natural catastrophes in Pegrema as has been suggested elsewhere. Cerealia pollen is recorded earlier than expected (c. 5000 B.P.=. In the Bronce Age and Iron Age, the settlement of the Zaonezhye peninsula is reflected by a slight increase in herb pollen representation, sporadic Cerealia pollen and several periods of regression in Picea. The long introductory period of agriculture to the area, as well as the similarities and discrepancies between different sources of evidence (palaeoecological, archaeological and historical) are discussed at some length. The start of land clearance for permanent cultivation in the profile Pegrema S was dated to the late 13^th century. The beginning of more intensive field cultivation in the 15^th century is clearly seen in the pollen succession at both localities. The fluctuation in anthropogenic indicators can be related to population density based on historical data. The village of Pegrema was depopulated in 1956 which is reflected in a distinct decline in settlement indicators. Received February 17 / Accepted May 19, 2000     

Vegetation in the mountains of northwest Iberia during the last glacial-interglacial transition

A new core taken from a site in the Sierra de Courel range of mountains in the northwest Iberian peninsula, Spain, enables a palaeoenvironmental reconstruction to be made of the biological events resulting from climatic changes and human activities during the last 17,000 years in the area. The sequence begins with a phase characterised by the dominance of Gramineae (Poaceae) and Pinus. A markedly arid period with prevalence of Artemisia pollen occurred between 17,5000 and 15,500 uncal. B.P. Subsequently, a succession of woodlands with Betula, Pinus and other mesophilous and thermophilous trees was recognised during the period 15,500-13,500 uncal. B.P. Between 13,500 and 10,300 uncal. B.P. herbaceous vegetation formations indicating moister conditions dominated the pollen record, although a maximum of Gramineae has been dated during the period 11,300-10,300 uncal. B.P. Comparison with other pollen data from neighbouring mountains allows an interpretation of the vegetation changes during the glacial/interglacial transition in the mountains of northwest Iberia. The Holocene pollen record from the site does not differ markedly from other records in the area, tree expansion occurring before 10,000 uncal. B.P. and high values of deciduous Quercus mixed with other trees and shrubs persisting until 3500 uncal. B.P., when increased human activities are shown by a fall of the tree pollen percentages. Received July 7, 1999 / Accepted May 22, 2000     

From forest to open pastures and fields: cultural landscape development in western Norway inferred from two pollen records representing different spatial scales of vegetation

The cultural landscape development of a farming community in western Norway was investigated through pollen analyses from a lake and a peat/soil profile. The pollen record from the lake indicates that there was a decrease in arboreal pollen (AP) by the end of the Mesolithic period (ca. 4200 cal b.c.), and that a substantial forest clearance occurred during the Bronze Age (ca. 1500 cal b.c.). The latter, together with grazing indicators and cereals, suggests a widespread establishment of farming. At the beginning of the Roman Iron Age there is an increase in heath communities. The pollen diagram from the peat/soil profile shows the forest clearance in the Bronze Age more clearly than the lake profile. This local pollen diagram is compared with modern pollen samples from mown and grazed localities in western Norway. Both analogue matching and ordination (PCA) indicate that the site was characterised by pastures and cereal fields from the Late Bronze Age to the Late Iron Age. An expansion of cereal cultivation took place during the Pre-Roman Iron Age, and an arable field was established at the site after ca. a.d. 800. This investigation illustrates the potential of selecting pollen sites reflecting different spatial scales, and complements the cultural history of the area as inferred from archaeological and historical records.     

On the Late Pleistocene and Holocene history of vegetation and human impact in the Ücker valley, north-eastern Germany

A high-resolution Late Pleistocene and Middle to Late Holocene pollen profile of regional significance is presented. The coring site is located in a mire between two lakes. Ober- and Unter-ückersee, in Brandenburg, north-eastern Germany. The study was carried out in an archaeological context. It provides information about the history of vegetation, climate and human impact in the ücker river valley and the surrounding hills, the Uckerm?rker Hügelland. Hence, it is an important contribution for the reconstruction of the past vegetation of this area of Brandenburg. Seven AMS ¹⁴C-dates based on pollen concentrates provide a chronology for the middle Holocene part of the profile. Phases of intensive human activity can be shown from the middle Neolithic times until the Roman Iron Age. Received February 1, 2000 / Accepted January 18, 2001     

Archaeobotanical evidence for early agriculture at Ljubjansko barje (Ljubljana Moor), central Slovenia

Archaeobotanical evidence is presented for early agriculture at southwestern Ljubljansko barje (Ljubljana Moor), Slovenia. Archaeobotanical finds from the Eneolithic site at Hočevarica, and pollen records from an archaeological profile and from a nearby core were analysed. Numerous charred grains of cultivated cereals together with fossil seeds of Chenopodium sp. demonstrate that during the occupation of the settlement at Hočevarica, agriculture was well established. The majority of identified grains were of Hordeum vulgare (cultivated barley) and the rest were Triticum monococcum and T. turgidum ssp. dicoccum (cultivated wheats). Large amounts of cereal pollen and pollen of Chenopodiaceae also suggest strong human impact on the surrounding vegetation and landscape. Pollen and archaeobotanical data from Hočevarica show a large consistency in timing of the appearance of agriculture. In the pollen record from the core at Hočevarica a significant increase (up to 40%) in cereal pollen was detected at 4881 ± 50 B.P. (3770-3630 cal B.C.). Charred cereal grains were dated to 4800 ± 40 B.P. (3650-3520 cal B.C.). The grains of cultivated cereals from Hočevarica represent the oldest archaeobotanical evidence for agriculture in central Slovenia. Received February 18, 2002 / Accepted October 21, 2002     

History of a Pinus strobus-dominated stand in northern New York

Abstract. Pollen, plant macrofossils and charcoal from a small forest hollow were analyzed to determine the formation and dynamics of a Pinus strobus-dominated forest stand on outwash soil in northern New York. P. strobus, Betula papyrifera and Abies balsamea colonized the upland surrounding the hollow following a major disturbance that occurred ca. 360 yr ago. Pre-disturbance vegetation consisted of shade-tolerant Tsuga canadensis, Fagus grandifolia and Picea ruhens. The size-class distribution of modern vegetation suggests continuing recruitment of A. balsamea and Acer rubrum at the site. The status of P. strobus and B. papyrifera in the stand is uncertain, but there is no evidence for recolonization of T. canadensis, F. grandifolia or P. rubens. Frequent windthrow has probably played a role in stand dynamics since ca. 310 yr BP due to the high wind-susceptibility of overstory and understory tree taxa in the modern forest patch. Vegetation change that occurred following fire(s) ca. 310 yr BP was recorded by plant macrofossils but not by pollen, indicating that the pollen assemblage was insensitive to vegetation change within at least 30 m (and potentially 60 m) of the hollow. The apparent insensitivity of this small-hollow pollen assemblage to local vegetation change may be related to the relatively large size of the hollow (75 m²) and/or to its close proximity to a 0.24 ha kettle pond.     

Past vegetation dynamics of Vltavský luh, upper Vltava river valley in the Šumava mountains. Czech Republic

Six pollen diagrams from peat bogs in the Vltavsky luh (upper Vltava river valley) provide new information about vegetation reconstruction, woodland dynamics, and local development of mires during the Late-glacial and Holocene. Vegetation development began in the Oldest Dryas/B?ling with open park plant cover. In the Aller?d, woodland with Pinus and Betula developed, and in the Younger Dryas there was a steppe tundra with plants of open habitats. In the Pre-boreal, woodland tundra grew. In the Boreal, Corylus spread, and a major expansion of Picea began in the early Boreal. Picea spread during the Atlantic probably by two different migration routes. Fagus immigrated earlier than in the Bayerischer Wald and Oberpf?lzer Wald in the adjoining parts of Germany, and had its major expansion in the early Atlantic. Abies expanded in the late Atlantic. The great abundance of Abies in this area is remarkable, forming Abies or Abies-Fagus woods in less extreme habitats. Human occupation started in the Sub-boreal, as shown by both archaeology and palynology. However, human impact is recognized from anthropogenic indicators which appear in the early Atlantic. At the end of the later Sub-atlantic the development of natural woodland was interrupted by plantation of Picea according to historical and palynological evidence. Received November 13, 2000 / Accepted July 7, 2001     

An experimental approach to Neolithic shifting cultivation

Archaeobotanical data from Late Neolithic lake-shore dwellings (4300-3500 cal B.C.) in the northern Pre-alpine lowlands are interpreted in different ways. The presence of permanent arable fields as well as arable fields with short fallow phases and shifting cultivation with slash-and-burn has been discussed. To test these hypotheses experimentally we have been conducting tests in a forest northeast of Stuttgart since 1994. The slightly south-exposed experimental area of approximately 4.5 ha on a loess soil is covered by mixed deciduous forest, is available for at least 20 years and has been divided into 34 plots of 30 × 30 m. Up to 2001, five plots were used for experiments. The normal procedure is clearing, burning the dry small timber (less than 10 cm in diameter) and then growing winter cereals (bread wheat) for one season. The yields were between 2000 and 4000 kg grains per ha. The harvest was more or less free from weeds. First attempts with summer crops gave much lower yields of about 1100 kg grains per ha. Continuous cereal growing on the same place in the following years resulted in minimal to zero yields, mainly due to vigorous weed growth. These weeds are not crop weeds, but forest perennials of clearings and forest fringes. Ploughing to remove the weeds is not possible, because of the presence of roots and tree-stumps, most of them still living. Weed regulation by hoeing, burning or cattle grazing remains to be tested. Protection of the crop from game and birds is by fences and nets, but protection from mice seems difficult. In the spectra from the pollen traps, clearing and burning are strongly indicated, but cereal growing only slightly. Received July 31, 2001 / Accepted April 9, 2002