Lars-Ake Larsson - Academia.edu (original) (raw)

Papers by Lars-Ake Larsson

With only the best crossdating members kept in the reference, this sample ANBL #### matches best ... more With only the best crossdating members kept in the reference, this sample ANBL #### matches best to 1487 (corrcoff=0.39). 1550 is then NOT to be considered (corrcoff=0.19)! ANBL #### The Rubens workshop may as well have reused old wood, anyhow splint is not available! ANBL #### Best match towards sum of published Neth+Belgium curves say 1487 at 0.37, 1550 at only 0.26.

Dendrochronologia

Abstract We present a brief overview of how to measure tree-ring widths in the software applicati... more Abstract We present a brief overview of how to measure tree-ring widths in the software application CooRecorder (Cybis Elektronik & Data AB) for tree-ring analysis complementing two video tutorials. The first tutorial covers the basics of opening files, measuring ring widths, preliminary crossdating with a reference chronology, and setting dates. The second tutorial covers setting earlywood-latewood boundaries, measuring across cracks, inserting locally absent or missing rings, manual adjustments, and metadata. The video tutorials can be found here https://www.youtube.com/watch?v=c-GNKHVUj9I and here https://www.youtube.com/watch?v=xO7Phc93xyM&t=3s . Videos have been closed-captioned in English.

Dendrochronologia, 2014

ABSTRACT Blue Intensity (BI) has the potential to provide information on past summer temperatures... more ABSTRACT Blue Intensity (BI) has the potential to provide information on past summer temperatures of a similar quality to maximum latewood density (MXD), but at a substantially reduced cost. This paper provides a methodological guide to the generation of BI data using a new and affordable BI measurement system; CooRecorder. Focussing on four sites in the Scottish Highlands from a wider network of 42 sites developed for the Scottish Pine Project, BI and MXD data from Scots pine (Pinus sylvestris L.) were used to facilitate a direct comparison between these parameters. A series of experiments aimed at identifying and addressing the limitations of BI suggest that while some potential limitations exist, these can be minimised by adhering to appropriate BI generation protocols. The comparison of BI data produced using different resin-extraction methods (acetone vs. ethanol) and measurement systems (CooRecorder vs. WinDendro) indicates that comparable results can be achieved. Using samples from the same trees, a comparison of both BI and MXD with instrumental climate data revealed that overall, BI performs as well as, if not better than, MXD in reconstructing past summer temperatures (BI r2 = 0.38 - 0.46; MXD r2 = 0.34 - 0.35). Although reconstructions developed using BI and MXD data appeared equally robust, BI chronologies were more sensitive to the choice of detrending method due to differences in the relative trends of non-detrended raw BI and MXD data. This observation suggests that the heartwood-sapwood colour difference is not entirely removed using either acetone or ethanol chemical treatment, which may ultimately pose a potential limitation for extracting centennial and longer timescale information when using BI data from tree species that exhibit a distinct heartwood-sapwood colour difference. Additional research is required in order to develop new methods to overcome this potential limitation. However, the ease with which BI data can be produced should help justify and recognise the role of this parameter as a potential alternative to MXD, particularly when MXD generation may be impractical or unfeasible for financial or other reasons.

The Holocene, 2012

Despite promising research in the 1980s showing the potential of Scots pine ( Pinus sylvestris L.... more Despite promising research in the 1980s showing the potential of Scots pine ( Pinus sylvestris L.) for the reconstruction of past summer temperatures in the Scottish Highlands, little dendroclimatic work has been attempted in this region since. This reflects, in part, the limited number of sparsely distributed remnant natural/semi-natural pine woodlands in the Scottish Highlands and the lack of old growth forest therein. On average, most of the pine trees dated in this region are around 225 years in age. Here, we present the first results of an ongoing interdisciplinary initiative to develop a long Scottish chronology through the acquisition of modern, historical and subfossil pine material from the native pinewoods, historic structures and lakes of the Scottish Highlands. Radiocarbon dating of 25 subfossil pine timbers recovered from lake sediments identified the presence of preserved material covering the last 8000 years with initial clusters focused on the last two millennia and ...

The Holocene

Maximum latewood density (MXD) is a strong proxy of summer temperatures. Despite this, there is a... more Maximum latewood density (MXD) is a strong proxy of summer temperatures. Despite this, there is a paucity of long MXD chronologies in the Northern Hemisphere, which limits large-scale tree-ring-based reconstructions of past temperature which are dominated by ring-width (RW) data – a weaker temperature proxy at inter-annual time-scales. This paucity likely results from the relative expense of measuring MXD and the lack of laboratories with the facilities to measure it. Herein, we test the ability of a relatively new, less expensive, tree-ring parameter, Blue Intensity (BI), to act as a surrogate parameter for MXD. BI was measured on Engelmann spruce samples from British Columbia where MXD had previously been measured to allow direct comparison between the two parameters. Signal strength analyses indicate that 8 MXD series were needed to acquire a robust mean chronology while BI needed 14. Utilising different detrending methods and parameter choices (RW + MXD vs RW + BI), a suite of r...

In the recent update (2022-08-31) of our article “Tree growth downturns in the Iron Age” we postu... more In the recent update (2022-08-31) of our article “Tree growth downturns in the Iron Age” we postulate that - due to a dendrochronological error of 218 years - an extreme narrow ring event in Scandinavian pine tree-ring chronologies at -329 CE is contemporary with the “Hallstatt gap” in central European oak tree-ring chronologies as well as the termination of the work at the old Hallstatt salt mine dated on dendrochronological grounds around -570. However, based on archaeological/radiocarbon evidence the Hallstatt settlement (its cemetery) was abandoned first around -350.

We further postulate a large cosmic catastrophe with impacts distributed over north-western Europe as the cause for the -329 extreme narrow ring event.

We added a postscriptum to the article (due to the consideration of recent research) on 2022-11-03.

An old preliminary manuscript from 2015 is still available here.

This is our contribution to the Thera debate. The Minoan eruption of the Thera (Santorini) volcan... more This is our contribution to the Thera debate.
The Minoan eruption of the Thera (Santorini) volcano provides an archaeological key marker for the Bronze Age chronology of the Eastern Mediterranean civilizations. However, the exact date for this large eruption is still unknown. Based on published tree ring and ice core chronologies, we investigate the candidates for major volcano eruptions in the middle of the second millennium BC.

Based on published and otherwise available tree-ring data, we have analyzed the dendrochronologic... more Based on published and otherwise available tree-ring data, we have analyzed the dendrochronological support for the current dating of Roman activities in western Europe. Manuscript rejected by Tree-Ring Research, details of peer review see: www.cybis.se/dendro

Supplementary data to "Dendrochronological dating of Roman time" is enclosed in a .zip file available here: https://www.researchgate.net/publication/349413026_SupplDataDendrochronologicalDatingRomanTimezip
Unzip it to an empty directory with e.g. Windows Explorer and then open the index.htm file with your browser.
This is the same data referred to in the original article as http://www.cybis.se/papers/data1.

Drafts by Lars-Ake Larsson

Having postulated and demonstrated that the Egyptian civil calendar was used strictly schematical... more Having postulated and demonstrated that the Egyptian civil calendar was used strictly schematically as a timekeeping instrument, we here investigate when and how the civil calendar was converted into the Alexandrian calendar. The surprising evidence shows that this happened in -37 CE and that a parallel calendar with the same start year and year length - known as the Spanish Era - was in operation until the 15 th century.

In this article we explore the papyrus archive from El Lahun using a strictly schematic Egyptian ... more In this article we explore the papyrus archive from El Lahun using a strictly schematic Egyptian civil calendar and a modern astronomical date for the start of the calendar. This leads to the absolute accession years for three pharaohs of the Egyptian 12 th dynasty. The accession years are compatible with recent radiocarbon dates for dynastic Egypt and are confirmed by all twenty-six moon dates with explicit regnal years, as well as by the Sothic date and an additional incomplete moon date included in the archive. Our investigation also sheds light on periods of co-regency, Egyptian practices of Sirius and moon observations, and the reliability of the Turin king list.

The rock-cut Great Temple at Abu Simbel in Nubia built by Rameses II has been associated with the... more The rock-cut Great Temple at Abu Simbel in Nubia built by Rameses II has been associated with the royal jubilee of the pharaoh. Based on our proposed accession year-1297, we can demonstrate that the first few jubilees of the king would have been celebrated when the traditional civil date for the festival (V Tybi 1) coincided with the climax of the autumnal lightshow at Abu Simbel. We regard this coincidence as a proof that we indeed have identified the absolute (astronomical) year for Rameses II's accession.

Using modern astronomical parameters and based on handed-down dates for "days of the Feast of the... more Using modern astronomical parameters and based on handed-down dates for "days of the Feast of the New Moon", we propose the exact accession years for two Egyptian New Kingdom pharaohs:-1497 for Thutmose III, and-1297 for Rameses II. These accession dates comply well with recent radiocarbon dates. We also include some remarks about the eight years adjustment of the radiocarbon calibration curve (Intcal) which we have applied in our Egyptological studies. As it appears just now, this eventuality seems to be at least detected-but not yet acknowledged-in recent academic research.

In this article we take a closer look at the Egyptian civil calendar and its primary sources to s... more In this article we take a closer look at the Egyptian civil calendar and its primary sources to see if this provides useful understanding for the Egyptian chronology. Scientific dates for e.g. the Egyptian New Kingdom do still not comply fully with the historical consensus chronology in force. This might be due to the lingering use of outdated scientific parameters, perhaps because of historical bias at Egypt's transition from sovereign kingdom to Roman province.

This article is about the historical consequences of our scientifically reinforced hypothesis tha... more This article is about the historical consequences of our scientifically reinforced hypothesis that the West-Roman empire is conventionally dated some 232 years too old. We offer an alternative interpretation of some Roman heirlooms retrieved from the grave of the Frankish king Childeric, and from a Japanese grave dated to the late 5th century.

This article is about a rarity: radiocarbon dates of timbers archaeologically anchored in West-Ro... more This article is about a rarity: radiocarbon dates of timbers archaeologically anchored in West-Roman time which are also dated by dendrochronology. The surprising but apparent trend is that the radiocarbon dates are a large number of years younger than the dendro dates. This strongly supports our hypothesis that West-Roman history and archaeology are conventionally dated too old by more than two hundred years, and that European dendrochronology was adapted to this error already in its early period.

In a new article in Dendrochronologia, Andreas Rzepecki with co-authors lift the lid on Ernst Hol... more In a new article in Dendrochronologia, Andreas Rzepecki with co-authors lift the lid on Ernst Hollstein's weak bridge over the Roman gap in the Central European oak chronology. This issue has been taboo since the bridge was accepted by academia. However, the authors do not deliver any scientific proof for their assertion that the bridge is still valid.
Our analysis shows that the generally used confidence levels for dendrochronological matches are still far too low to point out an unambiguous synchronous position. And in cases when a strong confidence level can not be reached with dendrochronology, the use of less resolved methods like radiocarbon, or even worse historical considerations, is still regarded an adequate procedure.

We empirically demonstrate that acceptance thresholds for a dendrochronological cross-match of at... more We empirically demonstrate that acceptance thresholds for a dendrochronological cross-match of at least t=6 for oak and at least t=7 for pine are required when constructing independent tree-ring master chronologies. These thresholds are far above the "thresholds for significant matches" of t=3.5 or t=4 adopted forty years ago, which are still regarded appropriate for the dating of archaeological samples. We also validate the supra-long Scots pine chronologies from northern Scandinavia using these tightened criteria and our crossdating software CDendro. The Finnish and Swedish pine chronologies were built by two concurrent teams of scientists working with wood from different places and with different methods. Both teams arrived at the same conclusion regarding the overall dendro signal for the past 7500 years. Our reassessment confirms this conclusion, and demonstrates that both teams worked on a firm level of confidence when accepting dendrochronological matches. This validation is vital for the credibility of our hypothesis about general errors in the European oak masters, errors which were probably caused by using pre-dating with other methods in cases when sufficient dendrochronological confidence levels could not be reached.

Cosmic abrupt radionuclide enrichment events provide a new exciting possibility for the exact dat... more Cosmic abrupt radionuclide enrichment events provide a new exciting possibility for the exact dating and synchronization of organic samples or annually resolved sequences of organic samples using 14 C measurement. Ice cores can be synchronized to the same events using 10 Be measurement instead. The two globally assured events in 775 and 994 have already proved the worth of this concept. We propose that a third event has been spotted between-2467 and-2465 in bristlecone pine, perhaps together with another event ten years later between-2457 and-2455. By detecting that double-event in wood from the Belfast Long chronology it would be possible to once and for all time determine a definitive date for this European key oak chronology. We also propose that Belfast Long has to be dated eight years earlier than conventionally assumed. This small offset would have far-reaching consequences for the internal linkage of the entire Belfast chronology, and moderate consequences for the radiocarbon calibration curve.

The Eastern Alpine Conifer Chronology is clearly synchronized with the European oak chronologies ... more The Eastern Alpine Conifer Chronology is clearly synchronized with the European oak chronologies over the recent 2500 years, thus confirming the long established dendrochronological bridge over the "Roman gap" which we dispute. We claim that the European timber complex archaeologically anchored in Roman time is conventionally dated too old by 218 years. But as the raw measurement data of the Alpine chronology is unpublished and unavailable we can not check whether our hypothesis is wrong, or the chronology is in error. However, some "outliers" in data derived from the chronology seem to tilt the scales in our favor.

Dendrochronologia

Dendrochronologia, 2014

The Holocene, 2012

The Holocene

We further postulate a large cosmic catastrophe with impacts distributed over north-western Europe as the cause for the -329 extreme narrow ring event.

We added a postscriptum to the article (due to the consideration of recent research) on 2022-11-03.

An old preliminary manuscript from 2015 is still available here.

Having postulated that the Christian era was inflated with 232 years already when it was invented... more Having postulated that the Christian era was inflated with 232 years already when it was invented at the transition from Late Antiquity to Early Medieval time, we are here looking for possible "twin events" with 232 years interval. These are major incisive events which were dated or reported multiple times in different historical contexts so that it seems that they happened twice.

We discuss the onset of the first plague pandemic and the destruction of the ancient city of Petra in Jordan. Both events are related to the development of Christianity within the Roman empire, which becomes a much more dynamic process with our hypothesis of a drastically reduced Late Antiquity, distinguished as a period of clustered natural catastrophes.

Published or otherwise available European oak tree-ring chronologies archaeologically anchored in... more Published or otherwise available European oak tree-ring chronologies archaeologically anchored in Roman time are all separated from early medieval chronologies by a severe timber depletion in late antiquity. Our recent dendrochronological study shows that this gap probably is unnecessarily wide because the Roman dendro complex as a whole appears dated too old by 218 years.

The subject of the here presented astronomical study was to investigate if there is additional scientific support for such a mistake which would mean a large calendar error in the Christian era. Our results indicate that the Christian era was inflated with 232 years already when it was invented. This was done by backdating West-Roman and related history by means of astronomical retrocalculation after the western part of the Roman empire had declined.

A remarkable result of our astronomical study is that the postulated astronomical/ historical error (232 years) appears to be offset by 14 years from the dendrochronological error (218 years). This means that, if we are right, then all current dendrochronological dates within the Roman time complex are given 14 years too young. According to our interpretation, the 14 years offset was caused by an improper synchronization of the Roman dendro complex towards Roman history done more than 30 years ago.