Woodborne Stephan

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Woodborne
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Stephan
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  • Article
    Radiocarbon investigation of a superlative Grandidier Baobab, the Big Reniala of Isosa
    (Universitatis Babes-Bolyai, Department of Chemistry, 2019) Patrut, Roxana T. ; Patrut, Adrian ; Pock-Tsy, Jean-Michel Leong ; Woodborne, Stephan ; Rakosy, Laszlo ; Danthu, Pascal ; Ratiu, Ileana-Andreea ; Bodis, Jeno ; von Reden, Karl F.
    The article discloses the accelerator mass spectrometry (AMS) radiocarbon dating results of the Big Reniala of Isosa, which is a massive Grandidier baobab (Adansonia grandidieri Baill.) of Madagascar. The investigation of this baobab shows that it consists of 5 perfectly fused stems and exhibits a cluster structure. The calculated wood volume of the tree is 540 m3, which makes the Big Reniala of Isosa the largest individual of all Adansonia species and also the biggest known angiosperm in terms of volume. Several samples were collected from the outer part of the stems. The oldest dated sample had a radiocarbon date of 934 ± 24 BP, which corresponds to a calibrated age of 845 ± 25 years. This value indicates an age of 1000 ± 100 years for the big Reniala of Isosa.
  • Article
    Final radiocarbon investigation of Platland tree, the biggest African baobab
    (Studia Chemia, 2017) Patrut, Adrian ; Woodborne, Stephan ; Patrut, Roxana T. ; Rakosy, Laszlo ; Hall, Grant ; Ratiu, Ileana ; von Reden, Karl F.
    The article discloses the main results of our new investigation of Platland tree, a.k.a. Sunland baobab, the largest known African baobab. Our recent research was motivated by the three successive splits of 2016 and 2017, which determined the collapse and demise of the stems that have built the main unit of the tree. According to our new findings concerning the architecture of large and old baobabs, we established that Platland tree has a double closed-ring shaped structure and consists of two units/rings that close two separate false cavities. The larger unit was composed of five fused stems, out of which four toppled and died, while the fifth stem is already broken. The smaller unit, which is still standing, consists of three fused stems. We also determined that the larger unit had an age of 800 yr, while the smaller unit is 1100 yr old.
  • Article
    Age, growth and death of a national icon: the historic Chapman baobab of Botswana
    (MDPI, 2019-11-05) Patrut, Adrian ; Woodborne, Stephan ; Patrut, Roxana T. ; Hall, Grant ; Rakosy, Laszlo ; Winterbach, Christiaan ; von Reden, Karl F.
    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.
  • Article
    African baobabs with false inner cavities : the radiocarbon investigation of the Lebombo Eco Trail Baobab
    (Public Library of Science, 2015-01-26) Patrut, Adrian ; Woodborne, Stephan ; von Reden, Karl F. ; Hall, Grant ; Hofmeyr, Michele ; Lowy, Daniel A. ; Patrut, Roxana T.
    The article reports the radiocarbon investigation results of the Lebombo Eco Trail tree, a representative African baobab from Mozambique. Several wood samples collected from the large inner cavity and from the outer part of the tree were investigated by AMS radiocarbon dating. According to dating results, the age values of all samples increase from the sampling point with the distance into the wood. For samples collected from the cavity walls, the increase of age values with the distance into the wood (up to a point of maximum age) represents a major anomaly. The only realistic explanation for this anomaly is that such inner cavities are, in fact, natural empty spaces between several fused stems disposed in a ring-shaped structure. We named them false cavities. Several important differences between normal cavities and false cavities are presented. Eventually, we dated other African baobabs with false inner cavities. We found that this new architecture enables baobabs to reach large sizes and old ages. The radiocarbon date of the oldest sample was 1425 ± 24 BP, which corresponds to a calibrated age of 1355 ± 15 yr. The dating results also show that the Lebombo baobab consists of five fused stems, with ages between 900 and 1400 years; these five stems build the complete ring. The ring and the false cavity closed 800–900 years ago. The results also indicate that the stems stopped growing toward the false cavity over the past 500 years.
  • Article
    Radiocarbon Investigation of the Historic African Baobabs of Omusati, Namibia
    (MDPI, 2022-11-11) Patrut, Adrian ; Patrut, Roxana T. ; Rakosy, Laszlo ; Rakosy, Demetra ; Oliver, Willie ; Ratiu, Ileana A. ; Lowy, Daniel A. ; Shiimbi, Gebhardt ; Woodborne, Stephan ; von Reden, Karl F.
    The Omusati region belongs to historic Ovamboland, an area of northern Namibia populated by tribes of the Ovambo group. Four very large African baobabs of Omusati played an important role in historic events of the area, such as the tribal wars and the Namibian War of Independence. The four historic baobabs are the Ombalantu baobab (8 stems; circumference 24.50 m), Okahao baobab (4+ stems; around 25 m), Amadhila baobab (12 stems; 25.35 m) and Sir Howard baobab (9 stems; 31.60 m). Two historic baobabs collapsed totally or partially. The stems of the Amadhila baobab toppled and died in 2021, while 3 stems of the Okahao baobab collapsed a long time ago, but are still alive. Our research aimed to determine the architecture and age of these baobabs. Three baobabs (Ombalantu, Amadhila, Sir Howard) exhibit a closed ring-shaped structure, with a false cavity inside. One baobab (Okahao) had an open ring-shaped structure, before its collapse. Several wood cores were extracted from the baobabs and investigated by radiocarbon dating. The dating results indicate ages of 770 ± 50 years for the Ombalantu baobab, 650 ± 50 years for the Okahao baobab, 1100 ± 50 years for the Amadhila baobab and 750 ± 50 years for the Sir Howard baobab.