Age, Growth and Death of a National Icon: The Historic Chapman Baobab of Botswana

The year 2016 witnessed the fall of a symbol of the botanical world: the historic Chapman baobab of Botswana. This article presents the results of our investigation of the standing and fallen tree. The Chapman baobab had an open ring-shaped structure composed of six partially fused stems. Several wood samples collected from the stems prior and after their collapse were analysed by using radiocarbon dating. The radiocarbon date of the oldest sample was 1381 ± 22 BP, which corresponds to a calibrated age of 1345 (+10, −15) calendar years. The dating results show that the six stems of the Chapman baobab belonged to three different generations, which were 1350–1400, 800–1000 and 500–600 years old. The growth rate variation of the largest and oldest stem is presented and correlated with the climate evolution in the area over the past 1000 years. The factors that determined the sudden fall and death of the Chapman baobab are also presented and discussed.

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Age and architecture of the largest African Baobabs from Mayotte, France

10.37281/preprints/1 ◽

2020 ◽

Author(s):

Adrian Patrut ◽

Roxana Patrut ◽

Laszlo Rakosy ◽

Karl von Reden

Keyword(s):

Life Cycle ◽

Radiocarbon Dating ◽

Cluster Structure ◽

Radiocarbon Date ◽

General State ◽

Adansonia Digitata ◽

Open Ring ◽

The Indian Ocean ◽

Ring Shaped Structure ◽

Comoro Islands

The volcanic Comoro Islands, located in the Indian Ocean in between mainland Africa and Madagascar, host several thousand African baobabs (Adansonia digitata). Most of them are found in Mayotte, which currently belongs to France, as an overseas department. We report the investigation of the largest two baobabs of Mayotte, the Big baobab of Musical Plage and the largest baobab of Plage N’Gouja. The Big baobab of Musical Plage exhibits a cluster structure and consists of 5 fused stems, out of which 4 are common stems and one is a false stem. The baobab of Plage N’Gouja has an open ring-shaped structure and consists of 7 partially fused stems, out of which 3 stems are large and old, while 4 are young. Several wood samples were collected from both baobabs and analyzed via radiocarbon dating. The oldest dated sample from the baobab of Musical Plage has a radiocarbon date of 275 ± 25 BP, which corresponds to a calibrated calendar age of 365 ± 15 yr. On its turn, the oldest sample from Plage N’Gouja has a radiocarbon date of 231 ± 20 BP, which translates into a calibrated age of 265 ± 15 yr. These results indicate that the Big baobab of Musical Plage is around 420 years old, while the baobab of Plage N’Gouja has an age close to 330 years. In present, both baobabs are in a general state of deterioration with many broken or damaged branches, and the Baobab of Plage N’Gouja has several missing stems. These observations suggest that the two baobabs are in decline and, most likely, close to the end of their life cycle.

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Age and architecture of the largest African Baobabs from Mayotte, France

10.37281/drcsf/1.1.5 ◽

2020 ◽

Vol 1 (1) ◽

pp. 33-47 ◽

Cited By ~ 1

Author(s):

Adrian Patrut ◽

Roxana T. Patrut ◽

Laszlo Rakosy ◽

Karl F. Von Reden

Keyword(s):

Radiocarbon Dating ◽

Cluster Structure ◽

Radiocarbon Date ◽

General State ◽

Adansonia Digitata ◽

Open Ring ◽

The Indian Ocean ◽

Paleoclimate Reconstructions ◽

Ring Shaped Structure ◽

Comoro Islands

The volcanic Comoro Islands, located in the Indian Ocean in between mainland Africa and Madagascar, host several thousand African baobabs (Adansonia digitata). Most of them are found in Mayotte, which currently belongs to France, as an overseas department. Baobabs constitute a reliable archive for climate change and millennial specimens were recently used as proxies for paleoclimate reconstructions in southern Africa. We report the investigation of the largest two baobabs of Mayotte, the Big baobab of Musical Plage and the largest baobab of Plage N’Gouja. The Big baobab of Musical Plage exhibits a cluster structure and consists of 5 fused stems, out of which 4 are common stems and one is a false stem. The baobab of Plage N’Gouja has an open ring-shaped structure and consists of 7 partially fused stems, out of which 3 stems are large and old, while 4 are young. Several wood samples were collected from both baobabs and analyzed via radiocarbon dating. The oldest dated sample from the baobab of Musical Plage has a radiocarbon date of 275 ± 25 BP, which corresponds to a calibrated calendar age of 365 ± 15 yr. On its turn, the oldest sample from Plage N’Gouja has a radiocarbon date of 231 ± 20 BP, corresponding to a calibrated age of 265 ± 15 yr. These results indicate that the Big baobab of Musical Plage is around 420 years old, while the baobab of Plage N’Gouja has an age close to 330 years. In present, both baobabs are in a general state of deterioration with many broken or damaged branches, and the Baobab of Plage N’Gouja has several missing stems. These observations suggest that the two baobabs are in decline and, most likely, close to the end of their life cycle.

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Combining Ancient DNA and Radiocarbon Dating Data to Increase Chronological Precision

10.1101/2020.09.18.300087 ◽

2020 ◽

Author(s):

Jakob W. Sedig ◽

Iñigo Olade ◽

Nick Patterson ◽

David Reich

Keyword(s):

Ancient Dna ◽

Radiocarbon Dating ◽

Dna Analysis ◽

Human Reproduction ◽

Radiocarbon Date ◽

The Past ◽

Ancient Dna Analysis ◽

Related Individuals ◽

Adna Analysis

AbstractThis paper examines how ancient DNA data can enhance radiocarbon dating. Because there is a limit to the number of years that can separate the dates of death of related individuals, the ability to identify first-, second-, and third-degree relatives through aDNA analysis can serve as a constraint on radiocarbon date range estimates. To determine the number of years that can separate related individuals, we modeled maximums derived from biological extremes of human reproduction and death ages and compiled data from historic and genealogical death records. We used these estimates to evaluate the date ranges of a global dataset of individuals that have been radiocarbon dated and for which ancient DNA analysis identified at least one relative. We found that many of these individuals could have their date ranges reduced by building in date of death separation constraints. We examined possible reasons for date discrepancies of related individuals, such as dating of different skeletal elements or wiggles in the radiocarbon curve. Our research demonstrates that when combined, radiocarbon dating and ancient DNA analysis can provide a refined and richer view of the past.

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Age and Growth Rate Dynamics of an Old African Baobab Determined by Radiocarbon Dating

Radiocarbon ◽

10.1017/s0033822200045744 ◽

2010 ◽

Vol 52 (2) ◽

pp. 727-734 ◽

Cited By ~ 10

Author(s):

Adrian Patrut ◽

Diana H Mayne ◽

Karl F von Reden ◽

Daniel A Lowy ◽

Sarah Venter ◽

...

Keyword(s):

Mass Spectrometry ◽

Growth Rate ◽

Radiocarbon Dating ◽

Age And Growth ◽

Sectional Area ◽

Adansonia Digitata ◽

Cross Sectional ◽

Volume Increase ◽

The Past ◽

Area Increase

In 2008, a large African baobab (Adansonia digitata L.) from Makulu Makete, South Africa, split vertically into 2 sections, revealing a large enclosed cavity. Several wood samples collected from the cavity were processed and radiocarbon dated by accelerator mass spectrometry (AMS) for determining the age and growth rate dynamics of the tree. The 14C date of the oldest sample was found to be of 1016 ± 22 BP, which corresponds to a calibrated age of 1000 ± 15 yr. Thus, the Makulu Makete tree, which eventually collapsed to the ground and died, becomes the second oldest African baobab dated accurately to at least 1000 yr. The conventional growth rate of the trunk, estimated by the radial increase, declined gradually over its life cycle. However, the growth rate expressed more adequately by the cross-sectional area increase and by the volume increase accelerated up to the age of 650 yr and remained almost constant over the past 450 yr.

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COMBINING ANCIENT DNA AND RADIOCARBON DATING DATA TO INCREASE CHRONOLOGICAL PRECISION

10.31235/osf.io/ru2w7 ◽

2020 ◽

Author(s):

Jakob Sedig ◽

Iñigo Olalde ◽

Nick Patterson ◽

David Reich

Keyword(s):

Ancient Dna ◽

Radiocarbon Dating ◽

Dna Analysis ◽

Human Reproduction ◽

Radiocarbon Date ◽

The Past ◽

Ancient Dna Analysis ◽

Related Individuals ◽

Adna Analysis

This paper examines how ancient DNA data can enhance radiocarbon dating. Because there is a limit to the number of years that can separate the dates of death of related individuals, the ability to identify first-, second-, and third-degree relatives through aDNA analysis can serve as a constraint on radiocarbon date range estimates. To determine the number of years that can separate related individuals, we modeled maximums derived from biological extremes of human reproduction and death ages and compiled data from historic and genealogical death records. We used these estimates to evaluate the date ranges of a global dataset of individuals that have been radiocarbon dated and for which ancient DNA analysis identified at least one relative. We found that many of these individuals could have their date ranges reduced by building in date of death separation constraints. We examined possible reasons for date discrepancies of related individuals, such as dating of different skeletal elements or wiggles in the radiocarbon curve. Our research demonstrates that when combined, radiocarbon dating and ancient DNA analysis can provide a refined and richer view of the past.

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ФОРМИРОВАНИЕ ПЕРЕХОДНОГО СЛОЯ ALN НА ТЕМПЛЕЙТАХ 3С-SIC/SI(111) МЕТОДОМ АММИАЧНОЙ МОЛЕКУЛЯРНО-ЛУЧЕВОЙ ЭПИТАКСИИ

Nanoindustry Russia ◽

10.22184/1993-8578.2020.13.3s.148.153 ◽

2020 ◽

Vol 96 (3s) ◽

pp. 148-153

Author(s):

С.Д. Федотов ◽

А.В. Бабаев ◽

В.Н. Стаценко ◽

К.А. Царик ◽

В.К. Неволин

Keyword(s):

Crystal Structure ◽

Growth Rate ◽

Low Temperature ◽

Surface Morphology ◽

Single Crystal ◽

Root Mean Square Roughness ◽

Rate Variation ◽

Mean Square ◽

Nucleation Layer ◽

Low Temperature Epitaxy

Представлены результаты изучения морфологии поверхности и структуры слоев AlN, сформированных аммиачной МЛЭ на темплейтах 3C-SiC/Si(111) on-axis- и 4° off-axis-разориентации. Опробован технологический режим низкотемпературной эпитаксии зародышевого слоя AlN на поверхности 3C-SiC(111). Среднеквадратичная шероховатость поверхности (5 х 5 мкм) слоев AlN толщиной 150 ± 50 нм составила 2,5-3,5 нм на темплейтах 3C-SiC/Si(111) on-axis и 3,3-3,5 нм на 4° off-axis. Показано уменьшение шероховатости смачивающего слоя AlN при изменении скорости роста. Получены монокристаллические слои AlN(0002) со значениями FWHM (ω-геометрия) 1,4-1,6°. The paper presents the surface morphology and crystal structure of AlN layers formed by ammonia MBE on 3C-SiC/Si(111) on-axis and 4° off-axis disorientation. It offers the technological approach of low-temperature epitaxy of the AlN nucleation layer on the 3C-SiC (111) surface. Root mean square roughness (5 х 5 |xm) of AlN layers with thickness of 150 ± 50 nm was 2,5-3,5 nm onto on-axis templates and 3.3-3.5 nm onto 4° off-axis. It appears that the RMS roughness of the AlN surface is changing with the growth rate variation. Single-crystal AlN(0002) layers with FWHM values (ω-geometry) of 1.4-1.6° have been obtained.

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Denitrifying pathways dominate nitrous oxide emissions from managed grassland during drought and rewetting

Science Advances ◽

10.1126/sciadv.abb7118 ◽

2021 ◽

Vol 7 (6) ◽

pp. eabb7118

Author(s):

E. Harris ◽

E. Diaz-Pines ◽

E. Stoll ◽

M. Schloter ◽

S. Schulz ◽

...

Keyword(s):

Growth Rate ◽

Nitrous Oxide ◽

N Fertilization ◽

High Variability ◽

Nitrous Oxide Emissions ◽

Severe Drought ◽

Total N ◽

The Past ◽

Precipitation Changes ◽

Isotopic Measurements

Nitrous oxide is a powerful greenhouse gas whose atmospheric growth rate has accelerated over the past decade. Most anthropogenic N2O emissions result from soil N fertilization, which is converted to N2O via oxic nitrification and anoxic denitrification pathways. Drought-affected soils are expected to be well oxygenated; however, using high-resolution isotopic measurements, we found that denitrifying pathways dominated N2O emissions during a severe drought applied to managed grassland. This was due to a reversible, drought-induced enrichment in nitrogen-bearing organic matter on soil microaggregates and suggested a strong role for chemo- or codenitrification. Throughout rewetting, denitrification dominated emissions, despite high variability in fluxes. Total N2O flux and denitrification contribution were significantly higher during rewetting than for control plots at the same soil moisture range. The observed feedbacks between precipitation changes induced by climate change and N2O emission pathways are sufficient to account for the accelerating N2O growth rate observed over the past decade.

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Disentangling the role of competition, light interception, and functional traits in tree growth rate variation in South Asian tropical moist forests

Forest Ecology and Management ◽

10.1016/j.foreco.2020.118908 ◽

2021 ◽

Vol 483 ◽

pp. 118908

Author(s):

Mizanur Rahman ◽

Masum Billah ◽

Md Obydur Rahman ◽

Debit Datta ◽

Muhammad Ahsanuzzaman ◽

...

Keyword(s):

Growth Rate ◽

Functional Traits ◽

South Asian ◽

Tree Growth ◽

Light Interception ◽

Rate Variation ◽

Tree Growth Rate

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SUITABILITY OF ACID-SOLUBLE AND ACID-INSOLUBLE LEATHER FRACTIONS IN RADIOCARBON DATING

Radiocarbon ◽

10.1017/rdc.2020.93 ◽

2020 ◽

pp. 1-8

Author(s):

Alyssa M Tate ◽

Brittany Hundman ◽

Jonathan Heile

Keyword(s):

Radiocarbon Dating ◽

Insoluble Fraction ◽

Economic Life ◽

Chemical Pretreatment ◽

Acid Base ◽

The Past ◽

Acid Soluble Collagen ◽

Method Of Production ◽

Insight Into

ABSTRACT Leather has been produced by a variety of methods throughout human history, providing researchers unique insight into multiple facets of social and economic life in the past. Archaeologically recovered leather is often fragile and poorly preserved, leading to the use of various conservation and restoration efforts that may include the application of fats, oils, or waxes. Such additives introduce exogenous carbon to the leather, contaminating the specimen. These contaminants, in addition to those accumulated during interment, must be removed through chemical pretreatment prior to radiocarbon (14C) dating to ensure accurate dating. DirectAMS utilizes organic solvents, acid-base-acid (ABA) and gelatinization for all leather samples. Collagen yield from leather samples is variable due to the method of production and the quality of preservation. However, evaluating the acid-soluble collagen fraction, when available, provides the most accurate 14C dates for leather samples. In instances where gelatinization does not yield sufficient material, the resulting acid-insoluble fraction may be dated. Here we examine the effectiveness of the combined organic solvent and ABA pretreatment with gelatinization for leather samples, as well as the suitability of the acid-insoluble fraction for 14C dating.

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