The cultivation of Castanea sativa (Mill.) in Europe, from its origin to its diffusion on a continental scale

The history of Castanea sativa (sweet chestnut) cultivation since medieval times has been well described on the basis of the very rich documentation available. Far fewer attempts have been made to give a historical synthesis of the events that led to the cultivation of sweet chestnut in much earlier times. In this article we attempt to reconstruct this part of the European history of chestnut cultivation and its early diffusion by use of different sources of information, such as pollen studies, archaeology, history and literature. Using this multidisciplinary approach, we have tried to identify the roles of the Greek and Roman civilizations in the dissemination of chestnut cultivation on a European scale. In particular, we show that use of the chestnut for food was not the primary driving force behind the introduction of the tree into Europe by the Romans. Apart from the Insubrian Region in the north of the Italian peninsula, no other centre of chestnut cultivation existed in Europe during the Roman period. The Romans may have introduced the idea of systematically cultivating and using chestnut. In certain cases they introduced the species itself; however no evidence of systematic planting of chestnut exists. The greatest interest in the management of chestnut for fruit production most probably developed after the Roman period and can be associated with the socio-economic structures of medieval times. It was then that self-sufficient cultures based on the cultivation of chestnut as a source of subsistence were forme

Influence of human impact and bedrock differences on the vegetational history of the Insubrian Southern Alps

Vegetation history for the study region is reconstructed on the basis of pollen, charcoal and AMS14C investigations of lake sediments from Lago del Segrino (calcareous bedrock) and Lago di Muzzano (siliceous bedrock). Late-glacial forests were characterised byBetula andPinus sylvestris. At the beginning of the Holocene they were replaced by temperate continental forest and shrub communities. A special type of temperate lowland forest, withAbies alba as the most important tree, was present in the period 8300 to 4500 B.P. Subsequently,Fagus, Quercus andAlnus glutinosa were the main forest components andA. alba ceased to be of importance.Castanea sativa andJuglans regia were probably introduced after forest clearance by fire during the first century A.D. On soils derived from siliceous bedrock,C. sativa was already dominant at ca. A.D. 200 (A.D. dates are in calendar years). In limestone areas, however,C. sativa failed to achieve a dominant role. After the introduction ofC. sativa, the main trees were initially oak (Quercus spp.) and later the walnut (Juglans regia). Ostrya carpinifolia became the dominant tree around Lago del Segrino only in the last 100-200 years though it had spread into the area at ca. 5000 cal. B.C. This recent expansion ofOstrya is confirmed at other sites and appears to be controlled by human disturbances involving especially clearance. It is argued that these forests should not be regarded as climax communities. It is suggested that under undisturbed succession they would develop into mixed deciduous forests consisting ofFraxinus excelsior, Tilia, Ulmus, Quercus andAce

Middle to Late Holocene vegetation history of the Upper Engadine (Swiss Alps): the role of man and fire

To reconstruct the vegetation and fire history of the Upper Engadine, two continuous sediment cores from Lej da Champfèr and Lej da San Murezzan (Upper Engadine Valley, southeastern Switzerland) were analysed for pollen, plant macrofossils, charcoal and kerogen. The chronologies of the cores are based on 38 radiocarbon dates. Pollen and macrofossil data suggest a rapid afforestation with Betula, Pinus sylvestris, Pinus cembra, and Larix decidua after the retreat of the glaciers from the lake catchments 11,000cal years ago. This vegetation type persisted until ca. 7300cal b.p. (5350b.c.) when Picea replaced Pinus cembra. Pollen indicative of human impact suggests that in this high-mountain region of the central Alps strong anthropogenic activities began during the Early Bronze Age (3900cal b.p., 1950b.c.). Local human settlements led to vegetational changes, promoting the expansion of Larix decidua and Alnus viridis. In the case of Larix, continuing land use and especially grazing after fire led to the formation of Larix meadows. The expansion of Alnus viridis was directly induced by fire, as evidenced by time-series analysis. Subsequently, the process of forest conversion into open landscapes continued for millennia and reached its maximum at the end of the Middle Ages at around 500cal b.p. (a.d.1450

Human impact on vegetation at the Alpine tree-line ecotone during the last millennium: lessons from high temporal and palynological resolution

Three mires and a small lake in the Swiss and Austrian Alps were studied palynologically at high resolution, covering the last 1,000, 400, 50 and 1,200years, respectively. Methodological lessons include: (1) Sub-decadal resolution in upper, little-decomposed peat layers reveals recurrent marked fluctuations in both percentages and influx of regional tree-pollen types, reflecting variations in pollen production rather than in plant-population sizes. (2) Intermittent, single-spectrum pollen maxima in samples of sub-decadal resolution indicate pollen transport in clumps. This type of pollen transport may remain unrecognized in sections with lower sampling resolution, which may then lead to inappropriate interpretation in terms of plant-population sizes. (3) The detection of short-lived phases of human impact in decomposed peat requires sampling intervals as close as 0.2cm. (4) PAR (pollen influx) may reflect vegetation dynamics more faithfully than percentages. Reliable PAR, however, is difficult to achieve in Alpine mires due to past human impact on peat growth, even when complex depth-age modelling techniques are used. Critical comparison of PAR with percentages is therefore essential. (5) Careful consideration of spatial scales in pollen signals (local-regional and subdivisions) is essential for a realistic palaeo-ecological interpretation. Results in terms of past human impact on vegetation are summarized as follows: (1) Trends in pollen types reflecting regional human action are in general agreement with earlier findings for the western Swiss Alps, allowing for regional differences. (2) All mires in the Alps investigated here and in an earlier study experienced human impact during the last millennium. The studied small lake, lying in sub-alpine pasture, records forest dynamics at a lower elevation since a.d. 80

A 700-year paleoecological record of boreal ecosystem responses to climatic variation from Alaska

Copyright by the Ecological Society of America © 2008. Willy Tinner, Christian Bigler, Sharon Gedye, Irene Gregory-Eaves, Richard T. Jones, Petra Kaltenrieder, Urs Krähenbühl, and Feng Sheng Hu 2008. A 700-YEAR PALEOECOLOGICAL RECORD OF BOREAL ECOSYSTEM RESPONSES TO CLIMATIC VARIATION FROM ALASKA. Ecology 89:729–743. http://dx.doi.org/10.1890/06-1420.1Recent observations and model simulations have highlighted the sensitivity of the forest–tundra ecotone to climatic forcing. In contrast, paleoecological studies have not provided evidence of tree-line fluctuations in response to Holocene climatic changes in Alaska, suggesting that the forest–tundra boundary in certain areas may be relatively stable at multicentennial to millennial time scales. We conducted a multiproxy study of sediment cores from an Alaskan lake near the altitudinal limits of key boreal-forest species. Paleoecological data were compared with independent climatic reconstructions to assess ecosystem responses of the forest–tundra boundary to Little Ice Age (LIA) climatic fluctuations. Pollen, diatom, charcoal, macrofossil, and magnetic analyses provide the first continuous record of vegetation–fire–climate interactions at decadal to centennial time scales during the past 700 years from southern Alaska. Boreal-forest diebacks characterized by declines of Picea mariana, P. glauca, and tree Betula occurred during the LIA (AD 1500–1800), whereas shrubs (Alnus viridis, Betula glandulosa/nana) and herbaceous taxa (Epilobium, Aconitum) expanded. Marked increases in charcoal abundance and changes in magnetic properties suggest increases in fire importance and soil erosion during the same period. In addition, the conspicuous reduction or disappearance of certain aquatic (e.g., Isoetes, Nuphar, Pediastrum) and wetland (Sphagnum) plants and major shifts in diatom assemblages suggest pronounced lake-level fluctuations and rapid ecosystem reorganization in response to LIA climatic deterioration. Our results imply that temperature shifts of 1–2°C, when accompanied by major changes in moisture balance, can greatly alter high-altitudinal terrestrial, wetland, and aquatic ecosystems, including conversion between boreal-forest tree line and tundra. The climatic and ecosystem variations in our study area appear to be coherent with changes in solar irradiance, suggesting that changes in solar activity contributed to the environmental instability of the past 700 years

Annual pollen traps reveal the complexity of climatic control on pollen productivity in Europe and the Caucasus

Annual PAR (pollen accumulation rates; grains cm−2year−1) were studied with modified Tauber traps situated in ten regions, in Poland (Roztocze), the Czech Republic (two regions in Krkonoše, two in Šumava), Switzerland (4 regions in the Alps), and Georgia (Lagodekhi). The time-series are 10-16years long, all ending in 2007. We calculated correlations between pollen data and climate. Pollen data are PAR summarized per region (4-7 traps selected per region) for each pollen type (9-14 per region) using log-transformed, detrended medians. Climate data are monthly temperature and precipitation measured at nearby stations, and their averages over all possible 2- to 6-month windows falling within the 20-month window ending with August, just prior to the yearly pollen-trap collection. Most PAR/climate relationships were found to differ both among pollen types and among regions, the latter probably due to differences among the study regions in the habitats of plant populations. Results shared by a number of regions can be summarized as follows. Summer warmth was found to enhance the following year's PAR of Picea, Pinus non-cembra, Larix and Fagus. Cool summers, in contrast, increase the PAR of Abies, Alnus viridis and Gramineae in the following year, while wet summers promote PAR of Quercus and Gramineae. Wetness and warmth in general were found to enhance PAR of Salix. Precipitation was found to be more important for PAR of Alnus glutinosa-type than temperature. Weather did not have an impact on the PAR of Gramineae, and possibly of Cyperaceae in the same year. Care is advised when extrapolating our results to PAR in pollen sequences, because there are large errors associated with PAR from sediments, due to the effects of taphonomy and sedimentation and high uncertainty in dating. In addition, in pollen sequences that have decadal to centennial rather than near-annual resolution, plant-interaction effects may easily out-weigh the weather signa

Early to late Holocene vegetation and fire dynamics at the treeline in the Maritime Alps

We used pollen, plant macrofossil, and charcoal records to investigate local long-term timberline shifts and changes in vegetation composition in relation to fire activity at the modern upper forest limit (ca. 2,000 m a.s.l.) in the Mont Bégo area, Maritime Alps of France and Italy. The area is an important place for Alpine archaeology because it has thousands rock-art carvings whose age cannot be directly assessed. Our new record confirms the occurrence of distinct land use phases (7,450–7,150, 6,200–4,900, and 4,250–3,700 cal bp), as suggested by earlier studies of rock art typology. Moreover, the vegetation reconstruction from macrofossils, with co-dominance of Pinus and Betula, suggests that early Holocene conditions were moister than in drier inner Alpine valleys, where Larix decidua played a more important role, both in the past as well as in modern timberline forests. After 8,000 cal bp, the timberline shifted upwards and mixed Abies alba and Pinus cembra stands established around the study site. These fire sensitive trees were finally replaced during the Bronze Age (around 4,000 cal bp) by L. decidua, which still dominates the subalpine woodlands in the area today. Our study supports the notion that while the range of A. alba has been reduced at the colder end of its natural distribution, that of L. decidua has been widened by land use changes and fire disturbances to create high alpine wood pastures

Holocene vegetation and fire history of the mountains of Northern Sicily (Italy)

Knowledge about vegetation and fire history of the mountains of Northern Sicily is scanty. We analysed five sites to fill this gap and used terrestrial plant macrofossils to establish robust radiocarbon chronologies. Palynological records from Gorgo Tondo, Gorgo Lungo, Marcato Cixé, Urgo Pietra Giordano and Gorgo Pollicino show that under natural or near natural conditions, deciduous forests (Quercus pubescens, Q. cerris, Fraxinus ornus, Ulmus), that included a substantial portion of evergreen broadleaved species (Q. suber, Q. ilex, Hedera helix), prevailed in the upper meso- mediterranean belt. Mesophilous deciduous and evergreen broadleaved trees (Fagus sylvatica, Ilex aquifolium) dominated in the natural or quasi-natural forests of the oro- mediterranean belt. Forests were repeatedly opened for agricultural purposes. Fire activity was closely associated with farming, providing evidence that burning was a primary land use tool since Neolithic times. Land use and fire activity intensified during the Early Neolithic at 5000 bc, at the onset of the Bronze Age at 2500 bc and at the onset of the Iron Age at 800 bc. Our data and previous studies suggest that the large majority of open land communities in Sicily, from the coastal lowlands to the mountain areas below the thorny-cushion Astragalus belt (ca. 1,800 m a.s.l.), would rapidly develop into forests if land use ceased. Mesophilous Fagus-Ilex forests developed under warm mid Holocene conditions and were resilient to the combined impacts of humans and climate. The past ecology suggests a resilience of these summer-drought adapted communities to climate warming of about 2 °C. Hence, they may be particularly suited to provide heat and drought-adapted Fagus sylvatica ecotypes for maintaining drought-sensitive Central European beech forests under global warming conditions

Revealing the last 13,500 years of environmental history from the multiproxy record of a mountain lake (Lago Enol, northern Iberian Peninsula)

This is the author's accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/s10933-009-9387-7.We present the Holocene sequence from Lago Enol (43°16′N, 4°59′W, 1,070 m a.s.l.), Cantabrian Mountains, northern Spain. A multiproxy analysis provided comprehensive information about regional humidity and temperature changes. The analysis included sedimentological descriptions, physical properties, organic carbon and carbonate content, mineralogy and geochemical composition together with biological proxies including diatom and ostracod assemblages. A detailed pollen study enabled reconstruction of variations in vegetation cover, which were interpreted in the context of climate changes and human impact. Four distinct stages were recognized for the last 13,500 years: (1) a cold and dry episode that includes the Younger Dryas event (13,500–11,600 cal. year BP); (2) a humid and warmer period characterizing the onset of the Holocene (11,600–8,700 cal. year BP); (3) a tendency toward a drier climate during the middle Holocene (8,700–4,650 cal. year BP); and (4) a return to humid conditions following landscape modification by human activity (pastoral activities, deforestation) in the late Holocene (4,650–2,200 cal. year BP). Superimposed on relatively stable landscape conditions (e.g. maintenance of well established forests), the typical environmental variability of the southern European region is observed at this site.The Spanish Inter-Ministry Commission of Science and Technology (CICYT), the Spanish National Parks agency, the European Commission, the Spanish Ministry of Science, and the European Social Fund

Preconception exposures and adverse pregnancy, birth and postpartum outcomes:Umbrella review of systematic reviews

Background Preconception exposures have been associated with adverse pregnancy, birth and postpartum outcomes. However, the reports, statements and guidelines of national and international health organisations vary in what they recommend individuals should monitor, avoid, reduce or practise in the preconception period. Objectives To synthesise and evaluate the evidence across systematic reviews for associations between exposures before conception and adverse pregnancy, birth and postpartum outcomes. Data sources MEDLINE, Embase, Epistemonikos (to May 2020) and reference lists of included reviews, without language or date restrictions. Study selection, data extraction and synthesis Systematic literature reviews of observational and/or interventional studies reporting associations between preconception exposures in women and/or men of reproductive age and pregnancy, birth or postpartum health outcomes were included. The methodological quality of reviews and the certainty of the evidence underlying each exposure-outcome association were assessed using AMSTAR 2 and the GRADE approach. Results We identified 53 eligible reviews reporting 205 unique exposure-outcome associations. Methodological quality was generally low with only two reviews rated as ‘high’ quality and two as ‘moderate’. We found high-certainty, randomised trial evidence that maternal folate supplementation reduces the risk of neural tube defects and anomaly-related terminations. Moderate-certainty, observational evidence was found that maternal physical activity is associated with reduced risk of pre-eclampsia and gestational diabetes, and that paternal age of ≥40 years and maternal body mass index (BMI) and interpregnancy weight gain are associated with increased risk of various adverse pregnancy and birth outcomes. Low- and very low-certainty evidence was found for other associations. Conclusions Clinicians and policymakers can be confident that maternal folate supplementation should be encouraged during the preconception period. There is moderate certainty in the evidence base that maternal physical activity, BMI and interpregnancy weight gain and advanced paternal age are important preconception considerations. High-quality research is required to better understand other exposure-outcome associations