| 1. |
- Ballesteros-Cánovas, Juan Antonio, et al.
(författare)
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Estimation of recent peat accumulation with tree saplings
- 2022
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Ingår i: Progress in Physical Geography. - : SAGE Publications. - 0309-1333. ; 46:4, s. 515-529
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this paper is to develop an approach to estimate peat accumulation rates (PAR) over recent decades based on the age and burial depths of roots from pine sapling and to use the newly developed approach to estimate spatial variations of PAR. To this end, we sampled 120 pine saplings growing in three plots at Rėkyva peatland in Lithuania and accounted for the microtopography around each specimen. In the lab, all saplings were cut into 1-cm segments, sanded and analysed. The counting of annual rings allowed dating the germination of each sapling with a yearly resolution and thus also enabled estimation of peat accumulation. The latter was derived by measuring the distance from the original root collar at germination to the ground level (or peat surface) at the time of sampling. The large number of samples selected from three plots also enabled determination of spatial variations in PAR. We obtain averaged PAR values of 1.6 ± 0.72 cm yr−1 across the three plots and over the last decades, but also observe strong spatial heterogeneity in PAR resulting from differences in local hydrology and vegetation. To validate the results, we compared tree-ring derived PAR with radiocarbon-based (14C) estimates at one of the plots. The results are consistent between the two approaches with PAR estimated to 0.8 and 0.79 cm yr−1, respectively, over the last 20 years. We conclude that PAR can be assessed accurately with tree-ring approaches and that they have clear advantages over radiocarbon dating for shorter timescales as they can be replicated more easily. For longer timescales and larger depths (> 15 cm), however, 14C dating remains the preferred approach.
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| 2. |
- Blanchet, Guillaume, et al.
(författare)
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Impacts of regional climatic fluctuations on radial growth of Siberian and Scots pine at Mukhrino mire (central-western Siberia)
- 2017
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 1879-1026 .- 0048-9697. ; 574, s. 1209-1216
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Tidskriftsartikel (refereegranskat)abstract
- Ring width (TRW) chronologies from Siberian (Pinus sibirica) and Scots (Pinus sylvestris) pine trees were sampled at Mukhrino - a large mire complex in central-western Siberia - to evaluate the impacts of hydroclimatic variability on tree growth over the last three centuries. For this purpose, we compared climate-growth correlation profiles from trees growing on peat soils with those growing on adjacent mineral soils. Tree growth at both peat and mineral soils was positively correlated to air temperature during the vegetation period. This finding can be explained by (i) the positive influence of temperature on plant physiological processes (i.e. growth control) during the growing season and (ii) the indirect impact of air temperatures on water table fluctuations. We observe also a strong link between TRW and the winter Palmer Drought Severity Index (PDSI), especially in Siberian pine, reflecting the isolating effect of snow and limited freezing damage in roots. Significant negative relations were, by contrast, observed between bog TRW chronologies and hydroclimatic indices during spring and summer; they are considered an expression of the negative impacts of high water levels and moist peat soils on root development. Some unusually old bog pines - exhibiting >500 growth rings - apparently colonized the site at the beginning of the Little Ice Age, and therefore seem to confirm that (i) peat conditions may have been drier in Siberia than in most other regions of western Europe during this period. At the same time, the bog trees also point to (ii) their strong dependence on surface conditions.
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| 3. |
- de Jong, Roelof S., et al.
(författare)
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4MOST-4-metre Multi-Object Spectroscopic Telescope
- 2014
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Ingår i: Ground-based and Airborne Instrumentation for Astronomy V. - : SPIE. - 0277-786X .- 1996-756X. ; 9147
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Konferensbidrag (refereegranskat)abstract
- 4MOST is a wide-field, high-multiplex spectroscopic survey facility under development for the VISTA telescope of the European Southern Observatory (ESO). Its main science drivers are in the fields of galactic archeology, high-energy physics, galaxy evolution and cosmology. 4MOST will in particular provide the spectroscopic complements to the large area surveys coming from space missions like Gaia, eROSITA, Euclid, and PLATO and from ground-based facilities like VISTA, VST, DES, LSST and SKA. The 4MOST baseline concept features a 2.5 degree diameter field-of-view with similar to 2400 fibres in the focal surface that are configured by a fibre positioner based on the tilting spine principle. The fibres feed two types of spectrographs; similar to 1600 fibres go to two spectrographs with resolution R> 5000 (lambda similar to 390-930 nm) and similar to 800 fibres to a spectrograph with R> 18,000 (lambda similar to 392-437 nm & 515-572 nm & 605-675 nm). Both types of spectrographs are fixed-configuration, three-channel spectrographs. 4MOST will have an unique operations concept in which 5 year public surveys from both the consortium and the ESO community will be combined and observed in parallel during each exposure, resulting in more than 25 million spectra of targets spread over a large fraction of the southern sky. The 4MOST Facility Simulator (4FS) was developed to demonstrate the feasibility of this observing concept. 4MOST has been accepted for implementation by ESO with operations expected to start by the end of 2020. This paper provides a top-level overview of the 4MOST facility, while other papers in these proceedings provide more detailed descriptions of the instrument concept[1], the instrument requirements development[2], the systems engineering implementation[3], the instrument model[4], the fibre positioner concepts[5], the fibre feed[6], and the spectrographs[7].
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| 6. |
- Edvardsson, Johannes, et al.
(författare)
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A multi-proxy reconstruction of moisture dynamics in a peatland ecosystem : A case study from Čepkeliai, Lithuania
- 2019
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Ingår i: Ecological Indicators. - : Elsevier BV. - 1470-160X. ; 106
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Tidskriftsartikel (refereegranskat)abstract
- In this study, six approaches were used to characterize hydrological changes in the Čepkeliai wetland complex (southeast Lithuania), namely (i) local water-table measurements (WTM), (ii) testate amoebae analysis, (iii) tree-ring width (TRW) series, (iv) peat stratigraphic data, (v) (hydro-) meteorological data (precipitation and river runoff), and (vi) a diachronic analysis of aerial photographs as well as historical maps. This multi-proxy framework provides complementary information on the hydrological evolution of the peatland and offers a unique opportunity to discuss the pros and cons of each approach. Local water-table measurements, for example, generated monthly resolved and precise (±0.01 m) hydrological information, but were limited to a 16-year period. On the other hand, the TRW data generated annually-resolved information linked to hydrological shifts over the period 1848–2018, but did not allow reconstruction of the amplitude of hydrological variations. Amongst the proxy records, the testate amoebae distribution is the only approach that gives a direct measurement of changes in water-table depths. At the same time, the approach is limited by chronological inaccuracies and weaker resolutions, similar to peat stratigraphic records. The meteorological data are theoretically representing the most highly resolved records. However, due to hydrological lags and feedbacks in peatlands, it was difficult to link regional changes observed in meteorological records to local changes in the peatland. The aerial photographs and historical maps offered an opportunity to document large-scale vegetation changes, which is useful for upscaling local results, but they may not capture rapid changes. Despite all these limitations, at Čepkeliai, most of the proxy records are in agreement with each other and suggest relatively moist conditions with water levels close to the peat surface during the late 1800s and early 1900s, followed by more detailed information towards the present showing shifts towards drier peat surface conditions during the 1930s and 1940s. The 1960s were dry, followed by a short, moist episode during the 1970s, and returning to drier conditions during the 1980s. A gradual change towards moister conditions was recorded over the 1990s and 2000s. The last decade in our records started with relatively wet conditions to end with lower water levels over the most recent years.
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| 7. |
- Edvardsson, Johannes, et al.
(författare)
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A statistical model for the prediction of the number of sapwood rings in Scots pine (Pinus sylvestris L.)
- 2022
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Ingår i: Dendrochronologia. - : Elsevier BV. - 1125-7865. ; 74
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Tidskriftsartikel (refereegranskat)abstract
- Dendrochronology is a well-established dating method for wooden objects, but due to surface processing of construction timber or natural degradation the dating of historical wood often relies on a prediction of the number of missing rings based on sapwood statistics. Since Scots pine (Pinus sylvestris L.) is one of the most common tree species in north-western Europe, the absence of reliable sapwood statistics and models for the prediction of missing sapwood rings for pine samples is remarkable. We have therefore produced sapwood statistics based on data from 776 pine trees with ages from 15 to 345 years. The material consists of both living trees and historical timber, with varying growth rates, geographic settings, and from different soil types. When the whole material is considered, the average age of the trees is 103 years, and the number of sapwood rings is 54 ± 15 (1 SD), but range from 18 to 129. Trees less than 100-years in age contained 46 ± 11 (1 SD) sapwood rings and had an average tree-ring width (TRW) of 1.76 mm. With increasing age, the average TRW decreased while the number of sapwood rings increased. The average TRW of 101–200-year-old trees is 0.99 mm while the samples contained 63 ± 12 (1 SD) sapwood rings. For trees older than 201 years, the average TRW is 0.64 mm while the number of sapwood rings increased to 85 ± 16 (1 SD). The two most important factors in determining the number of sapwood rings for a given tree when only heartwood statistics are available proved to be (i) the number of heartwood rings and (ii) the average TRW of the heartwood rings. For incomplete samples, we have therefore developed a statistical model based on the sample's heartwood rings (number and average width) to compute a prediction interval for the total number of rings. The sapwood and heartwood statistics suggest a statistical model for the number of sapwood rings with mean that increase with the number of heartwood rings. Furthermore, the average number of sapwood rings decreases with the mean width of the heartwood rings. However, the predictive power of the mean width is limited when the number of heartwood rings has already been taken into account. Thus, we suggest making predictions for the number of sapwood rings using only the number of heartwood rings. Predictions of the number of sapwood rings based on the statistical model where convincing in the case of the three different datasets that were analysed. The certainty in these predictions was such that the width of the 80% and 95% prediction intervals ranged 28–34 and 45–52 sapwood rings, respectively. Additionally, we demonstrate how make predictions when there is information about the number of remaining sapwood rings in a given sample. To make the sapwood model available, we present a free online R package for fitting our models and an online software dashboard.
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| 33. |
- Edvardsson, Johannes, et al.
(författare)
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Early Holocene bark-stripping damages as an indicator of large herbivores: Evidence from a submerged Mesolithic landscape in the Haväng area, southern Baltic basin
- 2021
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Ingår i: The Holocene. - : SAGE Publications. - 0959-6836 .- 1477-0911. ; 31:11-12, s. 1670-1680
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Tidskriftsartikel (refereegranskat)abstract
- A unique assemblage consisting of 113 pine samples collected from a submerged Mesolithic landscape in the Haväng area, southern Sweden, was examined to assess the presence of large herbivores, as well as changes in wild-game population density and composition. Bark-stripping damages on prehistoric trees is an extremely underutilized source of information about past game-population dynamics, yet our analyzes of wood samples – dated to around 10 500 cal. yr. BP – shows that such material can be successfully used to study the presence and activities of large herbivores, most likely ungulates. To evaluate our results, comparisons have been made with subfossil peatland trees that grew around 6000 years ago, as well as trees from two present day clearcut logging sites in southern Sweden. Furthermore, studies in a wild-game reserve were performed to recognize and understand different types of damages on trees caused by ungulates. Bark-stripping indicate the presence of ungulates, and the rate of damage is commonly associated with the density of the wild game. Bark-stripping was most frequently observed in the submerged wood material from the early Holocene, where damages were detected in 15% of the trees. In comparisons, 11% of the mid-Holocene trees show bark-stripping damages, whereas marks could be detected in the range between 0% and 6% of the trees from the two present-day clearcut logging sites. Our results show that tree-ring analyzes of prehistoric wood can generate information about wild-game dynamics of the past, and thereby being a valuable complement to more commonly used paleoecological and zooarcheological records.
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| 34. |
- Edvardsson, Johannes, et al.
(författare)
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Exploring climate forcing of growth depression in subfossil South Swedish bog pines using stable isotopes
- 2014
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Ingår i: Dendrochronologia. - : Elsevier BV. - 1125-7865. ; 32:1, s. 55-61
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Tidskriftsartikel (refereegranskat)abstract
- Comparison between growth variability, based on ring-width (RW) analysis, and moisture-sensitive signals in tree-ring carbon and oxygen stable-isotope composition provides increased understanding of how climate and hydrology influenced bog pines (Pinus sylvestris L) at two sites in southern Sweden during the mid- and late Holocene. Tree-ring sequences from two subfossil trees collected at raised bogs having different hydrology and catchment size were analyzed to probe the stable-isotope signals associated with two bog-wide episodes of growth depression, one during the Holocene Thermal Maximum and the other during the Neoglacial Transition. The occurrence of lower whole-wood delta C-13 and cellulose 813C and 8180 values immediately prior to the onset of growth depression in both trees, suggesting increased atmospheric relative humidity, is consistent with the notion that excessive effective moisture impeded tree growth. Correlation analysis indicates that the growth response lagged about three years behind the decline in delta C-13 and delta O-18 values in each tree, possibly reflecting relatively slow rise in the local water table in response to wetter climate. (c) 2013 Elsevier GmbH. All rights reserved.
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| 35. |
- Edvardsson, Johannes
(författare)
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Holocene climate change and peatland dynamics in southern Sweden based on tree-ring analysis of subfossil wood from peat deposits
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Dendrochronological analysis was applied to subfossil remains of Scots pine (Pinus sylvestris L.) buried in South Swedish peat deposits. By cross-dating Swedish bog-pine ring-width (RW) chronologies with corresponding material from North-west Germany, three Swedish RW chronologies were assigned absolute ages and yielded continuous, dated chronologies over the periods 5284-3728 BC and 2668-1108 BC. The obtained cross-match between RW chronologies from regions separated by 500-700 km is remarkably strong, which indicates that large-scale climate dynamics had a significant impact on bog-tree growth variability during the Holocene Thermal Maximum (HTM), a relatively warm and dry period generating favourable growth conditions on peatlands over large parts of North-west Europe. Nine additional RW chronologies, each about 200 years in length, were developed from pine, oak (Quercus robur L.) and alder (Alnus glutinosa L.). Most of these RW chronologies were dated by radiocarbon (14C). An approach combining bog-tree RW, replication and mean-age data, with peat stratigraphic records was explored to provide information about local hydrology, depositional history and peatland development. Registration of growth position of individual trees allowed assessment of the spatial dynamics of tree populations in response to hydrological changes and peatland development. Major bog-tree establishment and degeneration phases reflect changes in bog-surface wetness, often in response to climate-controlled groundwater fluctuations. Tree establishment phases coincide with stratigraphic layers of increased peat humification locally, and periods of increasing temperatures and widespread lake-level lowering regionally in southern Sweden. When conditions become more humid at the end of the HTM, increased lateral peatland expansion was recorded. This process could be studied in detail based on trees buried in the marginal zone of a peatland. An independent test of the hypothesis that bog-tree growth variability is controlled by effective moisture was performed by comparing RW data with tree-ring carbon (δ13C) and oxygen (δ18O) isotope records. Variations in the isotopic records confirm that growth depressions coincided with moister atmospheric conditions and reveal a lag of about three years in the growth response with respect to the isotopic signals, likely due to slow hydrologic response in the peatlands. This thesis demonstrates the usefulness of the South Swedish subfossil bog-tree material as a climate proxy with particular potential for decadal- to centennial-scale reconstructions of humidity fluctuations. It also demonstrates that subfossil bog-trees in combination with peat stratigraphy can be used for detailed reconstructions of peatland development and local groundwater variability, which are also highly relevant in a long-term regional palaeoclimatic context.
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| 36. |
- Edvardsson, Johannes, et al.
(författare)
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Holocene peatland development and hydrological variability inferred from bog-pine dendrochronology and peat stratigraphy - a case study from southern Sweden
- 2012
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Ingår i: Journal of Quaternary Science. - : Wiley. - 1099-1417 .- 0267-8179. ; 27:6, s. 553-563
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Tidskriftsartikel (refereegranskat)abstract
- Dendrochronological analysis was applied to subfossil remains of Scots pine (Pinus sylvestris L.) buried in a South Swedish peat deposit. In combination with peat stratigraphy, this approach was explored for its potential to provide information on the local hydrological and depositional history at the site, forming the basis for a regional palaeohydrological analysis. A 726-year ring-width chronology was developed and assigned an absolute age of 7233-6508cal a BP (5284-4559 BC) through cross-dating with German bog-pine chronologies, whereas two short additional records of older ages were radiocarbon dated. Registration of growth positions of individual trees allowed assessment of the spatial dynamics of the pine population in response to hydrological changes and peatland ontogeny. Annually resolved growth variability patterns in the pine population reveal several establishment and degeneration phases, probably reflecting fluctuations in bog-surface wetness. A major establishment phase at 7200-6900?cal a BP reflects the onset of a period of lowered groundwater level, also indicated by increased peat humification, and a development consistent with regional temperature and lake level reconstructions revealed from other proxies. This study demonstrates that subfossil bog-pine populations may provide annually to decadally resolved reconstructions of local groundwater variability, which are highly relevant in a long-term palaeoclimatic context. Copyright (c) 2012 John Wiley & Sons, Ltd.
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| 37. |
- Edvardsson, Johannes, et al.
(författare)
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How Cultural Heritage Studies Based on Dendrochronology Can Be Improved through Two-Way Communication
- 2021
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Ingår i: Forests. - : MDPI AG. - 1999-4907. ; 12:8
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Tidskriftsartikel (refereegranskat)abstract
- A significant part of our cultural heritage consists of wood. Research on historical wooden structures and artefacts thereby provides knowledge of people's daily lives and the society in which they lived. Dendrochronology is a well-established dating method of wood that can also provide valuable knowledge about climate dynamics, environmental changes, silviculture, and cultural transformations. However, dendrochronology comes with some limitations that end users in cultural heritage sciences must be aware of, otherwise their surveys may not be ultimately performed. We have drawn attention to studies in which dendrochronological results have been misinterpreted, over-interpreted, or not fully utilized. On the other hand, a rigorous dendrochronological survey may not respond to the request of information in practice. To bridge this rigour-relevance gap, this article has considered and reviewed both the dendrochronology's science-perspective and the practitioner's and end user's call for context appropriate studies. The material for this study consists of (i) interviews with researchers in dendrochronology and end users represented by cultural heritage researchers with focus on building conservation and building history in Sweden, and (ii) a review of dendrochronological reports and the literature where results from the reports have been interpreted. From these sources we can conclude that a continuous two-way communication between the dendrochronologists and end users often would have resulted in improved cultural heritage studies. The communication can take place in several steps. Firstly, the design of a sampling plan, which according to the current standard for sampling of cultural materials often is required, is an excellent common starting point for communication. Secondly, the survey reports could be developed with a more extensive general outline of the method and guidance in how to interpret the results. Thirdly, the potential contribution from dendrochronology is often underused, foreseeing historical information on local climate, silviculture, and choice of quality of the wooden resource, as the focus most often is the chronological dating. Finally, the interpretation of the results should consider all the available sources where dendrochronology is one stake for a conciliant conclusion.
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| 38. |
- Edvardsson, Johannes, et al.
(författare)
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Late-Holocene expansion of a south Swedish peatland and its impact on marginal ecosystems: Evidence from dendrochronology, peat stratigraphy and palaeobotanical data
- 2014
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Ingår i: The Holocene. - : SAGE Publications. - 0959-6836 .- 1477-0911. ; 24:4, s. 466-476
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Tidskriftsartikel (refereegranskat)abstract
- In this study, a reconstruction of the long-term development and lateral expansion of a south Swedish peat bog was performed using a multi-proxy approach, including dendrochronology, peat stratigraphy and macrofossil and pollen analyses. By combining mapping of cross-dated subfossil trees with radiocarbon-dated peat sequences, an improved approach to reconstruction of lateral peat expansion was applied. Apart from providing approximate ages of tree burial episodes, the ring-width records offer information on hydrological variations prior to the bog expansion. New bog oak, pine and alder chronologies are presented and their potential as a dating tool for peatland expansion as well as for local to regional environmental interpretations is examined. Our tree-replication records show that increased amounts of bog trees in the central parts can be linked to drier bog-surface conditions, whereas an increase in wood remains in the marginal zone is related to enhanced preservation due to lateral bog expansion. Our reconstructions of the development of the peat deposit and associated changes in the distribution of vegetation communities provide new insight into peatland responses to climate change at the end of the 'Holocene Thermal Maximum' (5000-4000 cal. yr BP).
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| 39. |
- Edvardsson, Johannes, et al.
(författare)
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Late-Holocene vegetation dynamics in response to a changing climate and anthropogenic influences – Insights from stratigraphic records and subfossil trees from southeast Lithuania
- 2018
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Ingår i: Quaternary Science Reviews. - : Elsevier BV. - 0277-3791. ; 185, s. 91-101
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Tidskriftsartikel (refereegranskat)abstract
- To increase our understanding of long-term climate dynamics and its effects on different ecosystems, palaeoclimatic and long-term botanical reconstructions need to be improved, in particular in underutilized geographical regions. In this study, vegetation, (hydro)climate, and land-use changes were documented at two southeast Lithuanian peatland complexes – Čepkeliai and Rieznyčia – for the Late-Holocene period. The documentation was based on a combination of pollen, plant macrofossils, peat stratigraphic records, and subfossil trees. Our results cover the last two millennia and reveal the existence of moist conditions in Southern Lithuania between 300 and 500 CE and from 950 to 1850 CE. Conversely, changes towards warmer and/or dryer conditions have been recorded in 100, 600, and 750 CE, and since the 1850s. Significant differences with other Baltic proxies prevent deriving a complete and precise long-term reconstruction of past hydroclimatic variability at the regional scale. Yet, our results provide an important cornerstone for an improved understanding of regional climate change, i.e. in a region for which only (i) few detailed palaeobotanical studies exist and which has, in addition, been considered as (ii) an ecologically sensitive region at the interface between the temperate and boreal bioclimatic zones.
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| 40. |
- Edvardsson, Johannes
(författare)
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Mid- to Late Holocene climate transition and moisture dynamics inferred from South Swedish tree-ring data
- 2016
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Ingår i: Journal of Quaternary Science. - : Wiley. - 1099-1417 .- 0267-8179. ; 31:3, s. 254-256
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Tidskriftsartikel (refereegranskat)abstract
- A 1561-year tree-ring width (TRW) chronology covering the period 2668–1108 BC (4617–3057 BP) has been developed from 159 moisture-sensitive peatland pines (Pinus sylvestris L.) sampled at Åbuamossen, southern Sweden. Tree population dynamics and annual growth responses of the trees were shown to reflect and give absolute age to regional hydro-climatological changes. The main wet-shifts recorded in the TRW data were precisely dated to 2150–2100, 1550 and 1230–1150 BC (4100–4050, 3500 and 3180–3000 BP) and are likely to be related to the stepwise Mid- to Late Holocene climate transition, during which the condition changed from relatively warm and dry towards cold and moist in the northern hemisphere. The tree-colonization phase was ended by several long-lasting periods showing depressed annual tree growth and an abrupt dying-off phase, possibly caused by increasing water level in the peatland as well as the adjacent river Helge Å. This study demonstrates that TRW data obtained from subfossil peatland trees can provide detailed information and exact age control on moisture variability in peatlands associated with regional hydroclimatic changes. Moreover, the combined information from the stratigraphical and the TRW analyses enabled a detailed temporal and spatial site development reconstruction.
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| 41. |
- Edvardsson, Johannes, et al.
(författare)
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Multiannual hydrological responses in Scots pine radial growth within raised bogs in southern Sweden
- 2015
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Ingår i: Silva Fennica. - : Finnish Society of Forest Science. - 2242-4075. ; 49:4, s. 1354-1354
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Tidskriftsartikel (refereegranskat)abstract
- To explore interactions between climate and peatland hydrology, Scots pine (Pinus sylvestris L.) growing at four raised bogs in southern Sweden were subject to a dendroclimatological study. Radial tree growth reflecting climate and water table fluctuations over multiannual periods was detected as significant negative correlations between tree-ring width (TRW) chronologies and the preceding one to four years total precipitation or river discharge. Systematically stronger negative correlations were obtained when river discharge instead of precipitation was compared to radial tree growth. This indicates that river discharge reflect moisture variability of peat bogs better than what precipitation data does. Meanwhile, monthly precipitation and radial tree growth did not show any clear correlation, whereas spring and early summer temperatures had a positive influence on the tree growth. Our study shows that growth variability of bog pines in the Boreal zone reflect hydrological responses related to a synthesis of climate controlled moisture variability over several year periods.
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| 42. |
- Edvardsson, Johannes, et al.
(författare)
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Old wood in a new light : an online dendrochronological database
- 2023
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Ingår i: International Journal of Wood Culture. - : Brill Academic Publishers. - 2772-3194 .- 2772-3186. ; 3:1-3, s. 442-463
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Tidskriftsartikel (refereegranskat)abstract
- The Old Wood in a New Light database project focuses on the digitization and accessibility of the results of dendrochronological samples analyzed and archived at four Swedish university-based tree-ring laboratories at Lund University, Stockholm University, University of Gothenburg, and the Swedish University of Agricultural Sciences. Collaboration with the Environmental Archaeology Laboratory and Humlab at Umeå University enables long-term open access to data, raw data, and metadata. In this project, we (1) systematically undertake large-scale entry and open access publication of results from wood samples scientifically analyzed and archived by Swedish laboratories and the associated metadata, into the Strategic Environmental Archaeology Database (SEAD; www.sead.se) research data infrastructure, and (2) actively promote the database as a resource for new and ongoing interdisciplinary research initiatives. Including dendrochronological data in SEAD infrastructure allows interdisciplinary studies that combine major scientific and societal questions. Building on a pilot study of construction timber from southern Sweden and adaptation of SEAD digitization workflows, more than 70 000 samples archived at the four dendrochronological laboratories are now being handled in the project. The broad coverage of research networks, stakeholder interaction, and strategic support from the cultural heritage community is guaranteed owing to the ongoing collaboration between laboratories and an established international and multidisciplinary reference group.
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| 43. |
- Edvardsson, Johannes, et al.
(författare)
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Periodicities in mid- to late-Holocene peatland hydrology identified from Swedish and Lithuanian tree-ring data
- 2016
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Ingår i: Quaternary Science Reviews. - : Elsevier BV. - 0277-3791 .- 1873-457X. ; 137, s. 200-208
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Tidskriftsartikel (refereegranskat)abstract
- Twenty-five tree-ring width (TRW) chronologies, developed from moisture sensitive peatland trees in Sweden and Lithuania, and representing eight periods during the mid-Holocene to present, were analysed regarding common periodicities (cycles). Periods of 13e15, 20e22, and 30e35 years were found in most chronologies, while 8e10, 18e19, and 60e65 year periodicities were observed as well, but less commonly. Similar periodicities, especially about 15 and 30 years in duration, were detected in both living and subfossil trees, indicating that the trees have responded to similar forcing mechanisms on those timescales through time. Some of the detected periods may be related to solar variability and lunar nodal tides, but most of the detected periodicities are more likely linked to hydrological changes in the peatlands associated to atmospheric patterns such as the North Atlantic Oscillation (NAO), or variations in sea surface temperatures (i.e. the Atlantic Multidecadal Oscillation, AMO). However, no significant relationships between tree growth, NAO and AMO could be formally established, possibly due to hydrological lag and feedback effects which are typical for peatlands but render in-depth assessments rather difficult.
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| 44. |
- Edvardsson, Johannes, et al.
(författare)
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Relation Between Success Rate and Sample Quantity in Dendrochronological Dating of Building Materials
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Ingår i: International Journal of Architectural Heritage. - 1558-3058.
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Tidskriftsartikel (refereegranskat)abstract
- Optimizing sample quantity and quality improves cost-effective and less invasive dendrochronological investigations. Our study examined 3,831 trees, including 2,921 pine, 404 spruce, and 506 oak trees. Pine had a 79.2% success rate for dating, spruce 46.5%, and oak 67.8%. Success rates increased with more trees analysed, notably in the case of spruce. When 1–3 spruce trees were analysed, only 44% yielded dating, while 8 or more trees achieved a 91.6% success rate. For pine, success rates ranged from 89% to 98%, and oak achieved success rates between 64% and 100%, depending on the number of trees analysed. The number of annual rings also had a significant impact. For spruce with 31–60 rings, only 33% could be dated, while pine and oak had higher dateability percentages at 60.1% and 48.6%, respectively. With 91–120 rings, dateability improved to 87.7% for pine, 75% for spruce, and 72.6% for oak. We observed temporal variations in dated material availability, likely due to shifts in building material usage over centuries. This study enhances our understanding of factors affecting sample requirements for successful dendrochronological analysis. While specific results have local relevance, the underlying principles and challenges apply globally, encouraging meaningful discussions between clients and dendrochronologists.
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| 45. |
- Edvardsson, Johannes, et al.
(författare)
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South Swedish bog pines as indicators of Mid-Holocene climate variability
- 2012
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Ingår i: Dendrochronologia. - : Elsevier BV. - 1125-7865. ; 30:2, s. 93-103
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Tidskriftsartikel (refereegranskat)abstract
- Dendroclimatic investigations of subfossil Scots pine (Pinus sylvestris) from two raised bogs in southern Sweden yielded a continuous floating 1492-year long tree-ring record. By cross-dating with bog-pine chronologies from Lower Saxony, Germany, the South Swedish record was assigned an absolute age of 5219-3728 BC. The cross-match between ring-width chronologies from these two regions, separated by 500-700 km, is remarkably strong and the correlation positive, which indicates that large-scale climate dynamics had a significant impact on the growth of bog pines during the Holocene Thermal Maximum (HTM) when bog-pine distribution reached a maximum in both regions. However, local population dynamics were also influenced by peatland ontogeny and competition, as shown by differences in replication and mean tree age between the Swedish and German records. Comparisons with chronologies developed from modern bog pines in southern Sweden indicate that more coherent climate was controlling pine growth on natural peatlands during warm periods in the past. This study demonstrates the usefulness of Swedish subfossil bog-pine material as a climate proxy, with particular potential for decadal- to centennial-scale reconstructions of humidity fluctuations. (C) 2011 Istituto Italiano di Dendrocronologia. Published by Elsevier GmbH. All rights reserved.
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| 46. |
- Edvardsson, Johannes, et al.
(författare)
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The Integrated Use of Dendrochronological Data and Paleoecological Records From Northwest European Peatlands and Lakes for Understanding Long-Term Ecological and Climatic Changes—A Review
- 2022
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Ingår i: Frontiers in Ecology and Evolution. - : Frontiers Media SA. - 2296-701X. ; 10
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Forskningsöversikt (refereegranskat)abstract
- Our overall understanding of long-term climate dynamics is largely based on proxy data generated from archives such as ice cores, ocean sediments, tree rings, speleothems, and corals, whereas reconstructions of long-term changes in vegetation and associated climate during the Holocene are largely based on paleoecological records from peat and lake sequences, primarily pollen and plant macrofossil data. However, since no proxy can provide a complete picture of the past, it is important to integrate different types of data, and to use methods that can support the paleoecological and paleoclimatic interpretations. Here we review how tree-ring data and dendrochronological approaches can be integrated with stratigraphic records to provide complementary paleoecological and paleoclimatic information. The review includes multiproxy studies in which dendrochronological data have been either compared or integrated with stratigraphic records, mainly pollen records, with the aim to contribute to a better understanding of long-term ecosystem and climate dynamics. We mainly focus on studies from northwest Europe in which tree-ring data and at least one type of paleoecological proxy record from the same site or area has been either compared or integrated. We find that integration of dendrochronological data and paleoecological records from peat and lake sequences is a powerful but underutilized approach to reconstruct long-term ecological and climatic changes. One likely reason for its limited use is the contrasting character of the two categories of data, including their different time resolution and occurrence, making them difficult to integrate. For example, subfossil wood providing annual dendrochronological data usually only occurs sporadically in peat and lake sediments, and the presence/absence of the trees are normally expected to be recorded in the pollen data with multi-decadal or coarser resolution. Therefore, we also discuss methods to compare and integrate dendrochronological and stratigraphic records, as well as the relevant paleoecological and paleoclimatic information provided by dendrochronology, pollen, and peat stratigraphy, with the aim to facilitate new multi-proxy initiatives that will contribute to a better understanding of long-term ecosystem and climate dynamics and thereby a firmer basis for future nature conservation initiatives.
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| 47. |
- Edvardsson, Johannes, et al.
(författare)
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The rediscovery of an Adoration of the Shepherds by Jacques Jordaens: : a multidisciplinary approach combining dendroarchaeology and art history
- 2021
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Ingår i: Heritage Science. - : Springer Science and Business Media LLC. - 2050-7445. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- The implementation of multidisciplinary research approaches is an essential prerequisite to obtain comprehensive insights into the life and works of the old masters and their timeline in the production of the arts. In this study, traditional art history, cultural heritage, and natural science methods were combined to shed light on an Adoration of the Shepherds painting by Jacques Jordaens (1593–1678), which until now had been considered as a copy. From dendrochronological analysis of the wooden support, it was concluded that the planks in the panel painting were made from Baltic oak trees felled after 1608. An independent dating based on the panel maker’s mark, and the guild’s quality control marks suggests a production period of the panel between 1617 and 1627. Furthermore, the size of the panel corresponds to the dimension known as salvator, which was commonly used for religious paintings during the period 1615 to 1621. Finally, the interpretation of the stylistic elements of the painting suggests that it was made by Jordaens between 1616 and 1618. To conclude, from the synthesis of: (i) dendrochronological analysis, (ii) panel makers’ punch mark and Antwerp Guild brand marks, (iii) re-examination of secondary sources, and (iv) stylistic comparisons to other Jordaens paintings, we suggest that the examined Adoration of the Shepherds should be considered as an original by Jordaens and likely painted in the period 1617–1618. The study is a striking example of the effectiveness of a multidisciplinary approach to investigate panel paintings.Introduction
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| 48. |
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| 49. |
- Edvardsson, Johannes, et al.
(författare)
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Water level impact on pine seedlings in greenhouse conditions : assessing growth and survival potential in ditched and managed peatlands
- 2024
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Ingår i: Scandinavian Journal of Forest Research. - 0282-7581 .- 1651-1891. ; 39:3-4, s. 199-210
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Tidskriftsartikel (refereegranskat)abstract
- Tree establishment on peatlands has various adverse effects on the environment, with one of the most significant being their transformation from carbon sinks to carbon sources. This transformation has largely been instigated by economic-driven ditching initiatives. In this study, 80 peat-rooted pine seedlings were subjected to hydrological scenarios corresponding to natural, ditched, and rewetted conditions to investigate how different management strategies affect tree growth and survival. The study was conducted in a greenhouse where all plants were exposed to identical conditions except for the water level, and focused on factors like stomatal conductance, plant survival, length, biomass, and radial tree growth. Wet conditions, specifically treatments rewetted and natural, resulted in consistently lower stomatal conductance compared to drier treatments. Plant survival was affected, with 15 deaths in the rewetted and 2 in natural groups. Moreover, length, biomass, radial growth, and cell formation were significantly lower for the groups exposed to wet conditions. Rewetting can therefore effectively control tree colonisations, and thereby preventing water consumption, litter fertilisation, and other positive feedback effects for the trees that might be negative for the carbon uptake and biodiversity in peatlands. This study thereby offers valuable insights for rewetting initiatives in tree colonised peatland ecosystems.
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| 50. |
- Helama, Samuli, et al.
(författare)
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Rereading a tree-ring database to illustrate depositional histories of subfossil trees
- 2017
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Ingår i: Palaeontologia Electronica. - 1935-3952. ; 20:1, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- Late Quaternary tree-ring chronologies have been constructed using data collected from subfossil trees preserved under favourable conditions in lake sediments and peat deposits. Tree-ring widths and densities are commonly used for reconstructions of past climate variability. An alternative way of using these data is to explore the replication curves of these chronologies. Here, we make use of previously collected data that is currently available from tree-ring databases to demonstrate the depositional histories of pine trees once accumulated into the sediment in lake (i.e., riparian trees) and peatland sites. Divergent courses of depositional histories were obtained for different sedimentary settings in southern Finland. Accumulation of peatland pines was high, but that of riparian trees was low around 1.0 ka during the Medieval Climate Anomaly (MCA). By contrast, the accumulation of peatland pines declined towards the Little Ice Age (LIA), while that of riparian trees increased, with a culmination around 0.7 ka. We interpret these variations to mean transitional environmental changes in the corresponding habitats and to indicate increased precipitation and a rising water table from MCA towards the LIA. These results demonstrate the relative roles of recruitment and preservation potentials, and thus of palaeoecological and taphonomic processes, in controlling the tree accumulation in peatland and lake environments, respectively. We conclude that subfossil tree-ring chronologies, even those extracted from electronic databases, can provide important insights into palaeoecology, furnishing new perspectives on palaeoclimate, palaeohydrology of lakes and peatlands, and for studying the tree population responses to past climatic changes.
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