Pinus Sylvestris Type Research Articles

Multiproxy analysis for the paleobiogeographical reconstruction of the relict forests of the Serranía de Ronda during the Holocene (Baetic System, Spain)

The mountains of the southern Iberian Peninsula are important biodiversity hotspots. They are also home to several relict species that are threatened with extinction in the face of global change. One of the best examples is the Serranía de Ronda, a system of mountainous reliefs located at the western end of the Baetic Cordillera. Its tree cover includes, among other unusual taxa, endemic formations such as the Spanish fir ( Abies pinsapo) and Portuguese oak ( Quercus faginea) forests. However, despite the ecological exceptionality of this mountainous area, little is known about its paleobiogeography. To remedy this, in this research we take a multidisciplinary approach based on the application of several different paleoecological disciplines, of which pedoanthracology is the main methodological tool. Six new soil surveys were performed, which were added to the existing pedoanthracological network, making a total of 43 soil sampling sites. The taxonomic analysis revealed several taxa, such as Abies, Fraxinus, Pinus and Pinus sylvestris-type, which are currently absent in several of the sampled sites. After contextualizing the 36 new radiocarbon dates obtained, the results confirm the antiquity of certain paleoendemic forests in the Serranía de Ronda, and the important role played by certain mountain enclaves as refuges for conifers such as A. pinsapo and Pinus sylvestris-type during the Pleistocene-Holocene transition. The dissemination of the results of this research will enable them to be implemented in the different strategies of adaptive management of the most threatened forests of the Serranía de Ronda.

Europe's southernmost interglacial refugia as sentinels for the local extinction of mountain conifers

The Serrania de Ronda is an exceptional palaeoecological laboratory for studying the dynamics of vegetation over time, due to its strategic geographical location at a biogeographical crossroads and its proven historical legacy. Many of the mountains that form part of this territory are today practically deforested, such as Sierra Blanca, whose geographic location at the heart of the Serranía de Ronda means that it has enormous potential as a biogeographical crossroads: the occasional presence of Abies pinsapo, Pinus pinaster and Quercus rotundifolia suggests that it was once covered by a mixed forest of conifers and broad-leaved trees. The lack of environmental research in Sierra Blanca has facilitated the installation of large quarries, which have led to its exclusion from the Sierra de las Nieves National Park, which was created in 2021. We applied the pedoanthracological methodology, which has enabled us to discover paleo-populations of A. pinsapo and Pinus sylvestris-type. The results confirm that coniferous forests previously covered a much wider area during the Holocene. These findings reinforce the role of Sierra Blanca as a high-altitude refuge for conifers during the warm stages of the Holocene and as a sentinel for the local extinction of mountain conifers. This information could help improve its management and conservation.

Eesti sürjametsad; nende tüübid ja indikaatorliigid

Abstract The aims of the study were: (i) to examine how well the hillock forests are distinguishable from the forests of comparable site types, (ii) to ascertain the hillock forest indicator species, (iii) to elucidate the hillock forests’ community types, (iv) to assess the practical requirement for differentiation of hillock forests as a self-sufficient typological unit for forestry. The data included altogether 160 descriptions of hillock forest communities and 42 relevés of other site type stands for comparison. The historical continuity of hillock forests was estimated from old topographic maps. We established that the hillock forests constitute statistically a reliable distinct group of forests. Among the characteristic species having an indicator value significance level of up to 0.50, by the ecological strategy 43.2% belong to competitors, 37.8% are competitors and stress-tolerant ruderals, and 10.8% competitors and stress tolerators; according to the hemeroby, 62.5% of these species are apophyts and 30.0% hemeradiaphors. Most hillock forests (55.6%) are located on former slash-and-burn areas (bushlands) or reforested agricultural land (36.1%). The hillock forests can be classified into four forest types: 1) Fragaria vesca–Festuca ovina–Pinus sylvestris type, 2) Fragaria vesca–Oxalis acetosella–Pinus sylvestris type, 3) Fragaria vesca–Viola mirabilis–Picea abies–Populus tremula type and, 4) Fragaria vesca–Equisetum pratense–Betula pendula type. There is no need to define the hillock forests as a separate forest site type in practical forest typology, nevertheless recognition of these forests as representing the habitat directive type 9060 is important from the viewpoint of biodiversity maintenance.

Well-designed mountain houses feature the only dated Pinus sylvestris type timbers in the southern French Alps

In the Southern French Alps, the Cervières Valley (near Briançon city) has traditional houses in which wood plays an important role, both in the buildings’ structures and in the activities of the humans who lived there. The six studied farms bear witness to an architecture perfectly adapted to the mountain environment and to the daily and seasonal activities of the inhabitants. Dendrochronology has revealed four major phases of logging from the 16th to the 19th century. The 90 sampled timbers are from larch and Scots pine type, and are of similar age and calibre. The choice of species for building was probably made on the basis of their proximity to the building site. However, until now we have not yet identified any Scots pine t. from before the 18th century in the buildings: does this represent a sampling bias or forest reality? Future historical and pedo-anthracological studies should provide answers. Although archaeological Scots pine is a recalcitrant species in dendroarchaeology in the Southern Alps, probably due to the presence of too many missing rings, in this study a Scots pine t. average has been dated on a larch reference chronology for the first time. This dating is supported by archaeological observations.

From forest to settlement: Magdalenian hunter-gatherer interactions with the wood vegetation environment based on anthracology and intra-site spatial distribution

This study aims to provide anthracological data on forest transformations on the north-eastern Iberian Peninsula during the transition from the last glacial GS-2a to the last isotopic event of interstadial GI-1. We present a complete anthracological sequence from Moli del Salt (Vimbodi i Poblet, Tarragona, NE Iberian Peninsula), a site assigned to the Late Upper Palaeolithic. Our results suggest a continuous forest cover transformation throughout the inter-GI-1. Forest opening was determined by the retreat of Pinus sylvestris type, which was dominant during the Late Pleistocene, in relation to the continuous expansion of Juniperus sp. Likewise, our results suggest a progressive increase in the diversity of cold- and drought-resistant mesophilic taxa, which would have begun with the more temperate climatic conditions occasioned by the positive isotopic oscillations of GI-1. A comparison with other paleoecological data from the Iberian Peninsula suggests the presence of different biogeographic regions, as evidenced by different frequencies of certain montane and meso-thermophilic taxa. Our research also made use of a new methodology based on the spatial distribution of the charcoal remains recovered from Late Magdalenian layer A of Moli del Salt. The results have provided data with which to evaluate the taphonomic alterations identified in the charcoal fragments, such as hyperfragmentation and the occurrence of postdepositional processes. This analysis has increased the temporal resolution of the archaeological fieldwork, allowing us to identify unique events of human activity in a context of cumulative palimpsests. Finally, the Kernel distributions according to the standard deviation of the tree taxa, projected both in plan (X-Y) and in section (X-Z1), indicate human strategies in fuel selection that differentiated between Pinus sylvestris type, Juniperus sp. and Prunus sp.

Coastal Pine-Oak Glacial Refugia in the Mediterranean Basin: A Biogeographic Approach Based on Charcoal Analysis and Spatial Modelling

During the glacial episodes of the Quaternary, European forests were restricted to small favourable spots, namely refugia, acting as biodiversity reservoirs. the Iberian, Italian and Balkan peninsulas have been considered as the main glacial refugia of trees in Europe. In this study, we estimate the composition of the last glacial forest in a coastal cave of the Cilento area (SW Italy) in seven time frames, spanning from the last Pleniglacial to the Late Glacial. Charcoal analyses were performed in seven archaeological layers. Furthermore, a paleoclimate modelling (Maxent) approach was used to complement the taxonomic identification of charcoal fragments to estimate the past potential distribution of tree species in Europe. Our results showed that the mesothermophilous forest survived in this region in the core of the Mediterranean basin during the Last Glacial Period (LGP, since ~36 ka cal BP), indicating that this area played an important role as a reservoir of woodland biodiversity. Here, Quercus pubescens was the most abundant component, followed by a wide variety of deciduous trees and Pinus nigra. Charcoal data also pointed at the crucial role of this coastal area, acting as a reservoir for warm temperate trees of genera Tilia, Carpinus and Sambucus, in LGP, in the Mediterranean region. Our modelling results showed that P. nigra might be the main candidate as a “Pinus sylvestris type” in the study site in the Last Glacial Maximum (LGM). Furthermore, we found that P. nigra might coexist with Q. pubescens in several European territories both currently and in the LGM. All models showed high levels of predictive performances. Our results highlight the advantage of combining different approaches such as charcoal analysis and ecological niche models to explore biogeographic questions about past and current forest distribution, with important implications to inform today’s forest management and conservation.

Impact of climatic extremes on Alpine ecosystems during MIS 3

The effects of climatic extremes on Alpine ecosystems, such as in the last glacial period, are poorly understood. The recently discovered Nesseltalgraben site is currently the best dated and most complete high-resolution sedimentary sequence in the northern Alps covering the Marine Isotope Stage (MIS) 3 around 59-28 calibrated kiloyears before present (ka cal BP). The MIS 3 is a period with frequent climatic fluctuations known as Dansgaard-Oeschger cycles or Greenland interstadials-stadials. Here, we present pollen assemblages, bryophyte macrofossils, and stable isotopes (δ2H, δ13C, δ18O) from the Nesseltalgraben to elucidate palaeoenvironments and palaeoclimatic variability during that period. In addition to bulk sedimentary cellulose, also cellulose extracted from fossil wood, monocots, and bryophytes was analysed isotopically. Among the terrestrial pollen, Poaceae and arboreal pollen show an antithetic behaviour reflecting interstadial-stadial variations. Arboreal pollen are dominated by Pinus sylvestris-type, with admixtures of Picea, Betula, Alnus, and Salix. The arboreal pollen record exhibits several maxima indicating milder climatic conditions tentatively assigned to Greenland interstadials 17–14, 12/11, 8, and 6. During Heinrich events 5 and 4, the arboreal pollen record shows distinct minima underlining a severe impact of these events on regional climate and vegetation. Bryophyte assemblages show predominant wetland conditions at the site during the entire MIS 3. The sudden occurrence of the bryophyte Drepanocladus turgescens after 31.6 ka cal BP indicates a change from a fen to a frequently drying wetland environment. This habitat change is presumably linked to enhanced glaciofluvial action caused by glaciers approaching the site. Carbon, hydrogen, and oxygen stable isotope records of bulk sedimentary cellulose exhibit comparably stable conditions from 59 until 52 ka cal BP and increased values around 51 ka cal BP followed by a period of almost absent cellulose until 39 ka cal BP. Thereafter, and lasting until 30 ka cal BP, bulk sedimentary cellulose isotope records (δ2H, δ13C, and δ18O) reveal strongly fluctuating values. These isotope variations are interpreted as variable mixtures between terrestrial lignified plants and monocots on the one, and wetland bryophyte sources on the other hand. A strong negative isotope excursion in the bulk sedimentary and the bryophyte cellulose records around 36.4 ka cal BP is contemporaneous with maximum Cyperaceae pollen and best explained by progressively waterlogged soils due to permafrost. The rise in the bryophyte δ18O record thereafter, accompanied by likewise increasing δ13C values, most likely indicates an enhanced evaporation of source waters.

Montane pine forests in NE Iberia during MIS 3 and MIS 2. A study based on new anthracological evidence from Cova Gran (Santa Linya, Iberian Pre-Pyrenees)

This study aims to characterize forest landscapes during the Late Middle Paleolithic (LMP), Early Upper Paleolithic (EUP) and Magdalenian of the NE Iberian Upper Pleistocene. In this paper we present the results of anthracological analyses from Cova Gran (Santa Linya, Spain). Results show a dominance of Pinus sylvestris type suggesting that despite the occurrence of climate changes throughout the Upper Pleistocene forest cover was continuous. The data, from Cova Gran is analyzed from a regional perspective through comparison with other sequences in the NE Iberia region. The comparison suggests a dominance of Pinus sylvestris type from the coast to the Pyrenees. Comparison with other sequences from Northern Iberia shows differences regarding the presence of cryophillous pines in some phases and a higher diversity and the presence of other plant communities. This contributes to the understanding of the local environmental differences according to the biogeographical setting of the sites. The present study also suggests that pines were available in NE Iberia throughout the Upper Pleistocene and was systematically used as the main source of firewood.

Holocene vegetation history of the Jeseníky Mts: Deepening elevational contrast in pollen assemblages since late prehistory

AbstractQuestionsHow did the vegetation of a Central European mountain region with a fragmented alpine zone develop during the Holocene? When did human land use start to alter summit grasslands? Which gradient in pollen assemblages was strongest and was it consistent through time?LocationJeseníky Mountains, Czech Republic.MethodsSixteen pollen records were subjected to DCA in order to explore patterns of compositional similarities in the fossil pollen data. Because only the last 6,000 years were recorded in the study sites from mountain summits, we restricted further analysis to this period. Twelve radiocarbon‐dated pollen records were subjected to DCCA constrained by modelled calibrated age. Responses of individual pollen types to the principal DCCA gradients were tested with GAMs.ResultsIn the DCA, Early Holocene samples were located close to recent ones due to abundant pollen of herbs, Poaceae, Betula, Pinus sylvestris type and rare pollen of climax deciduous trees. In the DCCA for the last 6,000 years, the sorting of sites along the first unconstrained axis correlated with altitude, which is a complex factor corresponding to temperature and geomorphology (flat summits vs alluvia of mountain rivulets). This elevational differentiation became more pronounced after 2,250 cal BP when summit peatlands started to contain more Vaccinium, Calluna vulgaris, Amaranthaceae, Plantago lanceolata and Rumex acetosa type pollen. In contrast, mid‐elevation pollen spectra started to contain more meadow herbs (Caltha, Potentilla type, Cirsium/Carduus). Picea pollen was surprisingly more associated with mid‐elevation than high‐elevation sites, unlike Fagus.ConclusionIncreasing contrast between summits and middle elevation alluvia seems to be a major feature of vegetation development over the last 6,000 years. While alluvial areas were encroached by Alnus–Picea forests, and later locally transformed into wet grasslands, grazing and forest burning at summits gradually increased abundance of acidophytic dwarf shrubs and peatlands, especially since the Iron Age. Human impact might facilitate beech expansion at high elevations, with Picea‐dominated forests being restricted to alluvia and around mid‐elevation basin peatlands prior to establishment of modern Picea plantations.

Reconstruction of the palaeoenvironment and anthropogenic activity from the Upper Pleistocene/Holocene anthracological records of the NE Iberian Peninsula (Barcelona, Spain)

This paper presents the results of anthracological analyses conducted to further the palaeoenvironmental reconstruction of NE Iberia and to provide better insights into the impact of human activity on the landscape. This study is based on the analysis of charred plant remains from five archaeological sites located ∼20 km to the southwest of the city of Barcelona. The site chronology spans from the Upper Pleistocene to the mid-Holocene. The MIS 5-stage is represented by the Cova del Rinoceront (ca. 74–175 ka), which yielded scarce anthracological remains, composed primarily of angiosperms. MIS 3 and the HS4 stadial are represented by the Cova del Coll Verdaguer (ca. 33.4–55 ka) and the Terrasses de la Riera dels Canyars (39.6 ka cal BP) respectively, both pointing to the recurrent presence of Pinus sylvestris type. The Holocene record is represented by the Cova Bonica (ca. 7200–4600 cal BP), presenting a predominance of Quercus, Pinus and a considerable variability of shrubs and small tree types. Finally, Cal Maurici (ca. 6100–3700 cal BP) constitutes a natural deposit in shallow marshes, and presents charcoals washed down the river. The sequence presented is completed and compared with other sequences located in NE Iberia. The assemblages allow us to evaluate the evolution and transformation of the forested landscapes originated by the climate variations that occurred during the Upper Pleistocene and Holocene and to assess changes in the woody vegetation resulting from cultural or natural transformations. These outcomes are discussed in terms of a comparison of natural vs. anthropogenic anthracological records and the data are contextualized and examined in the broader context of the other assemblages recovered in the NE Iberian Peninsula.

Late Quaternary developments of Mediterranean oaks in the Atlantic domain of the Iberian Peninsula: The case of the Cantabrian region (N Spain)

Abstract A synthesis of the occurrence of the evergreen oak (Quercus ilex-type) in the Cantabrian region (northern Spain) is presented on the basis of integrated charcoal and pollen analyses. Archaeological charcoal comes largely from sites along the littoral and pre-littoral territories of the Basque Country, Cantabria and Asturias dated from 45 to 3.7 Kyr cal BP, and culturally ranging from Mousterian to Iron Age. Pollen information is produced from a few archaeological sites but mainly from peats and lake sediments. Q. ilex-type is observed as early as at 45-30 Kyr cal BP, with sporadic occurrences in vegetation contexts dominated by Pinus sylvestris-type, which was widely exploited by Mousterian and Aurignacian inhabitants. Afterwards, during the Upper Palaeolithic, there is an important decline, and Q. ilex-type is hardly present between 29 and 15 Kyr cal BP, with open environments dominated by heathland shrubs. From Late Magdalenian onwards, Q. ilex-type expanded again, remaining in the landscape of the Cantabrian region throughout the Holocene, although subordinated in deciduous oak forests under the influence of oceanic climate conditions. Q. ilex-type had a more favourable position than deciduous Quercus across the Cantabrian southern slopes and northwest of the adjacent Iberian Cordillera, where oceanic influences have become attenuated by summer drought and continentality.

Fuel exploitation among Neanderthals based on the anthracological record from Abric Romaní (Capellades, NE Spain)

Abstract Fuel is a basic resource enabling energy production, and its exploitation was a major activity in Neanderthal daily life. In this work we present charcoal results obtained from the Abric Romani site in order to evaluate fuel use among the human groups occupying this rock shelter from 40 to 70 ka BP. The Abric Romani, a Middle Palaeolithic site, has yielded evidence of a well-preserved sequence of Neanderthal occupations. The results of this taxonomic and taphonomic study have allowed us to characterise the charcoal assemblage as mainly comprising Pinus sylvestris type. This assemblage gives us an understanding of Neanderthal fuel acquisition strategies, mobility and occupation patterns.

Pollen and macrofossil analyses of Pliocene lacustrine sediments (Salto river valley, Central Italy)

The study of two sedimentary records sampled in the fluvio-lacustrine succession of high Salto river valley (Rieti, central Italy) was originated in the frame of the Geomorphologic Map of Italy ( APAT, 2008) field survey and improved with a multidisciplinary approach addressed to a better knowledge of the Plio-Pleistocene continental environments of central Apennines. The two successions are associated to different sedimentary facies, with lateral heteropic relations: the deposits cropping out at Marano de' Marsi are thought to represent deposition in the distal portion of a lacustrine delta, while those of Borgorose took place in a frankly lacustrine environment. The sediment succession from Marano de' Marsi (11 m) was sampled from an outcrop, the one from Borgorose (24.5 m) from a drillhole. Palaeomagnetic investigations carried out on both sediment records indicate a normal magnetic polarity and very low magnetic susceptibility values. In the record from Marano de' Marsi section, gymnosperm pollen is prevailing. Four main and short angiosperm arboreal pollen oscillations can however be observed, the oldest of which more marked. The gymnosperms are mainly represented by Pinus haploxylon type, Pinus sylvestris type, Cedrus, Picea, Abies, Cathaya, Tsuga, Taxodium type. Among angiosperms the dominant taxa, some of which at present extinct in Italy, are Quercus, Zelkova, Ulmus, Carya and Pterocarya. The presence of pollen of subtropical taxa as Nyssa, cfr. Rhoiptelea, Liquidambar, Engelhardia is worth to be mentioned. The investigation was integrated also by a preliminary study of macrofossils. Fossil impressions with some organic matter of angiosperm and gymnosperm leaves and seeds/fruits were ascribed to Acer cfr. monspessulanum, Carpinus cfr. orientalis, Engelhardia, Fagus, Hedera, Liquidambar, Quercus, Rosa, Abies and Pinus. The 24.5 m long sediment core from Borgorose resulted very poor in pollen, with the same list of arboreal taxa, at present extinct in Italy, found at Marano de' Marsi, and a diagram was drawn only for the stretch of the core between 3 and 8.2 m. Gymnosperms ( P. haploxylon type is dominant, and accompanied by P. sylvestris type, Picea, Taxodium type, Cedrus, and Tsuga) are always prevailing. The results obtained by this interdisciplinary investigation indicate that Marano de' Marsi and Borgorose successions can be possibly attributed to the Upper Pliocene (normal polarity Olduvai subchron) even if an older age, considering the present state of the art on Pliocene continental records, and the peculiarity of the site and of the region, cannot be excluded.

Late glacial and Holocene vegetation, Indian monsoon and westerly circulation in the Trans-Himalaya recorded in the lacustrine pollen sequence from Tso Kar, Ladakh, NW India

Palynological investigation of a 410 cm long core section from Tso Kar (33°10′N, 78°00′E, 4527 m a.s.l.), an alpine lake situated in the arid Ladakh area of NW India at the limit of the present-day Indian summer monsoon, was performed in order to reconstruct post-glacial regional vegetation and climate dynamics. The area was covered with alpine desert vegetation from ca. 15.2 to 14 kyr BP (1 kyr = 1000 cal. years), reflecting dry and cold conditions. High influx values of long-distance transported Pinus sylvestris type pollen suggest prevailing air flow from the west and northwest. The spread of alpine meadow communities and local aquatic vegetation is a weak sign of climate amelioration after ca. 14 kyr BP. Pollen data (e.g. influx values of Pinus roxburghii type and Quercus) suggest that this was due to a strengthening of the summer monsoon and the reduced activity of westerly winds. The further spread of Artemisia and species-rich meadows occurred in response to improved moisture conditions between ca. 12.9 and 12.5 kyr BP. The subsequent change towards drier desert-steppe vegetation likely indicates more frequent westerly disturbances and associated snowfalls, which favoured the persistence of alpine meadows on edaphically moist sites. The spread of Chenopodiaceae-dominated vegetation associated with an extremely weak monsoon occurred at ca. 12.2–11.8 kyr BP during the Younger Dryas interstadial. A major increase in humidity is inferred from the development of Artemisia-dominated steppe and wet alpine meadows with Gentianaceae after the late glacial/early Holocene transition in response to the strengthening of the summer monsoon. Monsoonal influence reached maximum activity in the Tso Kar region between ca. 10.9 and 9.2 kyr BP. The subsequent development of the alpine meadow, steppe and desert-steppe vegetation points to a moderate reduction in the moisture supply, which can be linked to the weaker summer monsoon and the accompanying enhancement of the winter westerly flow from ca. 9.2 to 4.8 kyr BP. The highest water levels of Tso Kar around 8 kyr BP probably reflect combined effect of both monsoonal and westerly influence in the region. An abrupt shift towards aridity in the Tso Kar region occurred after ca. 4.8 kyr BP, as evidenced by an expansion of Chenopodiaceae-dominated desert-steppe. Low pollen influx values registered ca. 2.8–1.3 kyr BP suggest scarce vegetation cover and unfavourable growing conditions likely associated with a further weakening of the Indian Monsoon.

Holocene hydrological and vegetation changes in southern France inferred by the study of an alluvial travertine system (Saint-Guilhem-le-Désert, Hérault)

A geobotanical study of the travertine system of Saint-Guilhem-le-Désert (southern France) was carried out in order to reconstruct the local Holocene environment in a region where the postglacial vegetation history is poorly documented. The travertinisation process has started at ca. 8500 cal. BP, in a landscape dominated by Pinus sylvestris type (probably Pinus nigra sub sp. salzmannii). Around 7000 cal. BP, the travertine system recorded torrential events not evidenced at the regional scale, showing the particularity of the Verdus hydrological regime. More recently, ca. 5100 cal. BP, a lake or a marsh was filled within the Verdus plain, as attested to by sand and silt particles accumulated in the sequence. The present-day vegetation dominated by Quercus ilex, on south facing slopes, was most likely established between the Bronze Age and the Gallo-Roman period correlatively to the decline of Pinus nigra and deciduous Quercus, most probably under human influence.

Description and differentiation of Pseudolarix amabilis pollen Palaeoecological implications and new identification key to fresh bisaccate pollen

The differentiation of Pseudolarix from other bisaccate pollen is considered as a tool to investigate the fossil history of this genus. Using Light Microscope (LM) and Scanning Electron Microscopy (SEM) we performed a descriptive and morphometric analysis of Pseudolarix amabilis (Pinaceae) bisaccate fresh pollen grains. Descriptive differentiation characters from Pinus and from other bisaccates have been established. A morphometric differentiation from pine pollen belonging to Pinus sylvestris type was obtained through a study of twelve living species of Pinus. A new identification key for bisaccate pollen grains of living conifers has been elaborated. Although it is addressed to identification of fresh pollen, the proposed descriptive criteria may also be applicable to well-preserved fossil material. A Pliocene site from N-Italy, rich in Pseudolarix cone scales and needles, was used to test the reliability of the proposed criteria on fossil pollen. We also identified Pseudolarix pollen from the lacustrine sediments from Massif Central (France), about 3 My. We carried out a complementary evaluation of the ecological and climate ranges both of the living species and of the fossil assemblages that included Pseudolarix. This tree was a component of the warm-temperate mixed conifers rainforests of the Cenozoic, a biome yielding, after considerable reduction of floristic diversity, overall conifer decimation, to the modern “mixed mesophytic” and “mixed hardwood” forest types. Although its fossil record reveals a wide distribution in the Northern Hemisphere during the Cenozoic, macrofossils are only scattered. On the other hand, information about the pollen production, aerodynamics and taphonomy of Pseudolarix pollen suggests that this tree is among the properly or moderately over-represented genera in pollen images from its natural habitat. Therefore, its pollen record may add clarifications to palaeoclimate reconstructions of Cenozoic environments.

Vegetation of the Lago de Sanabria area (NW Iberia) since the end of the Pleistocene: a palaeoecological reconstruction on the basis of two new pollen sequences

Various pollen sequences from lacustrine deposits close to Lago de Sanabria (NW Iberia) have for several decades been a key source of information for palaeoenvironmental reconstructions of SW Europe, though their interpretation has been the subject of some controversy. Here we present two new pollen sequences obtained from this area, and a new palaeoenvironmental reconstruction of the region. The available pollen data reach back to before 18,000 b.p., a period of very harsh climate with seasonal (non continuous) sedimentation and a landscape characterised by herbaceous formations dominated by Gramineae and Artemisia, and scrub formations dominated by Ericaceae and Cistaceae. Subsequently sedimentation became continuous, and various regional forest expansions are apparent. At a local level, the first forest expansion began about 12,000 b.p., when Betula pollen reached 70% followed by peaks in Pinus sylvestris-type (>80%) and Quercus robur-type (40%). The Younger Dryas saw a retreat of woodland formations in the area around the lake, with broadleaved deciduous woodland (largely oak) retreating at mid and low altitudes, but with pine woodland persisting in more sheltered sites. The climatic improvement in the Early Holocene favoured re-expansion of woodland, dominated by Pinus sylvestris-type at higher and Quercus robur and Q. pyrenaica at lower altitudes, until anthropogenic deforestation commenced around 4,000 b.p. The disappearance of natural pine woodlands in this region is probably largely attributable to human interference.

Postglacial vegetation history in Luxembourg: new charcoal data from the cave of la Karelslé (Waldbillig, eastern Gutland)

The archaeological site of La Karelsle (Waldbillig, Luxembourg) provides the first important charcoal sequence in Luxembourg for the development of Holocene plant cover. During the Pre-boreal, the results show open woodland vegetation dominated by Pinus sylvestris type in association with Betula sp. and Rosaceae. After an important gap covering the Boreal and the early Atlantic, the data reveal the dominance of a deciduous Quercus woodland with Tilia sp., Fraxinus excelsior and Corylus avellana. Finally during the sub-Boreal, the assemblages indicate a cooler and wetter climate and Quercus woods with Fagus sylvatica and Taxus baccata. There is no clear evidence for human impact.