1. Adrian Patrut, Stephan Woodborne, Karl F. von Reden, Grant Hall, Michele Hofmeyr, Daniel A. Lowy, Roxana T. Patrut, African Baobabs with False Inner Cavities: The Radiocarbon Investigation of the Lebombo Eco Trail baobab, PLoS ONE, 2015, 10(1): e0117193. doi: 10.1371/journal.pone.0117193.

Abstract. 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.

2. Adrian Patrut, Karl F. von Reden, Pascal Danthu, Jean-Michel Leong Pock-Tsy, Roxana T. Patrut, Daniel A. Lowy, Searching for the oldest baobab of Madagascar: Radiocarbon investigation of large Adansonia rubrostipa trees, PLoS ONE,  2015, 10(3): e0121170. doi: 10.1371/journal.pone.0121170.

Abstract. The article reports the AMS radiocarbon investigation of the two largest known Adansonia grandidieri specimens. The two baobabs, which are named Tsitakakoike and Pregnant baobab, are located in Southwestern Madagascar, near Andombiro. A third specimen from this area, the House baobab, was also investigated. According to measurements, Tsitakakoike is the biggest individual above ground level of all Adansonia species. The House baobab was selected for its exposed structure, which is identical to the closed ring-shaped structure with false cavities identified by us in large and old Adansonia digitata specimens. According to our research, Tsitakakoike and the Pregnant baobab have multi-stemmed cylindrical trunks which are mainly hollow; the two very large baobabs also possess a ring-shaped structure. The radiocarbon dates of the oldest wood samples collected from the large trunks were 1274 ± 20 bp for Tsitakakoike and 930 ± 20 bp for the Pregnant baobab. According to their original positions and to the architectures of the two Adansonia grandidieri, the ages of Tsitakakoike and Pregnant baobab would be between 1300-1500 years. Therefore, Adansonia grandidieri becomes the third Adansonia species with individuals that can live over 1000 years, according to accurate dating results.

3. Stephan Woodborne, Grant Hall, Iain Robertson, Adrian Patrut, Mathieu Rouault, Neil J. Loader, Michele Hofmeyr, A 1000-year carbon isotope rainfall proxy record from South African baobab trees (Adansonia digitata L.), PLoS ONE, 2015, 10(5): e0124202. doi: 10.1371/journal.pone.0124202.

Abstract. A proxy rainfall record for northeastern South Africa based on carbon isotope analysis of four baobab (Adansonia digitata L.) trees shows centennial and decadal scale variability over the last 1000 years.  The record is in good agreement with a 200-year tree ring record from Zimbabwe, and it indicates the existence of a rainfall dipole between the summer and winter rainfall areas of South Africa. The wettest period was c. AD 1075 in the Medieval Warm Period, and the driest periods were c. AD 1635, c. AD 1695 and c. AD1805 during the Little Ice Age. Decadal-scale variability suggests that the rainfall forcing mechanisms are a complex interaction between proximal and distal factors. Higher rainfall oscillations are significantly associated with lower sea-surface temperatures in the Agulhas Current core region and a negative Dipole Moment Index in the Indian Ocean. The correlation between rainfall and the El Niño/Southern Oscillation Index is non-static with temporal inversions in the rainfall response. The effect is weak and it appears that the El Niño phenomenon is an enabling rather than a causative contributor to rainfall variability. The effect of both proximal and distal oceanic influences are insufficient to explain the rainfall change between the Medieval Warm Period and the Little Ice Age, and the evidence suggests that this was the result of a northward shift of the subtropical westerlies rather than a southward shift of the Intertropical Convergence Zone.

4. Adrian Patrut, Karl F. von Reden, Pascal Danthu, Jean-Michel Leong Pock-Tsy, Laszlo Rakosy, Roxana T. Patrut, Daniel A. Lowy, Dragos Margineanu, AMS radiocarbon dating of very large Grandidier’s baobabs (Adansonia grandidieri), Nucl. Instr. Meth. B (Nuclear Instruments and Methods in Physics Section B), 2015, 361: 591-598. doi: 10.1016/ j.nimb.2015.04.044.

Abstract. 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.

5. Adrian Patrut, Stephan. Woodborne, Roxana T. Patrut, Grant Hall, Laszlo Rakosy, Karl F. von Reden, Daniel A. Lowy, Dragos Margineanu, Radiocarbon dating of African baobabs with two false cavities: The investigation of Luna tree, Studia UBB Chemia, 2015, LX, 4, 7-20.

Abstract. The paper discloses the radiocarbon investigation results of the Luna tree, a representative African baobab from Venetia Limpopo Nature Reserve, South Africa. Several wood samples collected from deep incisions in the trunk were investigated by AMS (accelerator mass spectrometry) radiocarbon dating. The age sequence of segments extracted from the oldest sample demonstrates that ages increase with the distance into the wood up to a point of maximum age, after which ages  decrease toward the sample end. This anomaly is typical for multi-stemmed baobabs, having a closed ring-shaped structure with a false cavity inside. Dating results reveal that each of the two large fused units, which build the Luna tree, consist of such a closed ring. The two closed rings include two interconnected false inner cavities. False cavities are empty spaces between fused stems that were never filled with wood. We named this baobab architecture, which has a very high symmetry, double closed ring-shaped structure with two false cavities. The new architecture, which is very uncommon, enables baobabs to reach large sizes and very old ages. The radiocarbon date of the oldest sample segment was 1507 ± 22 bp, which corresponds to a calibrated age of 1405 ± 20 yr. We estimate that the oldest part of Luna tree has an age of 1600 ± 100 yr. By these results, the Luna tree becomes the fourth oldest African baobab with accurate dating results.

6. Adrian Patrut, Roxana T. Patrut, Pascal Danthu, Jean-Michel Leong Pock-Tsy, Laszlo Rakosy, Daniel A. Lowy, Karl F. von Reden, AMS radiocarbon dating of large za baobabs (Adansonia  za) of Madagascar, PLoS ONE, 2016, 11(1), e0146977. doi:10.1371/journal.pone.0146977.

Abstract. The article reports the radiocarbon investigation results of Anzapalivoro, the largest za baobab (Adansonia za) specimen of Madagascar. Several wood samples collected from the large inner cavity and from the outer part/exterior of the tree were investigated by AMS (accelerator mass spectrometry) radiocarbon dating. For samples collected from the cavity walls, the age values increase with the distance into the wood up to a point of maximum age, after which the values decrease toward the outer part. This anomaly of age sequences indicates that the inner cavity of Anzapalivoro is a false cavity, practically an empty space between several fused stems disposed in a ring-shaped structure. The radiocarbon date of the oldest sample was 710 ± 25 BP, which corresponds to a calibrated age of 675 ± 20 yr. Dating results indicate that Anzapalivoro has a closed ring-shaped structure, which consists of 5 fused stems that close a false cavity. The oldest part of the biggest za baobab has a calculated age of 850 years. We also dated a second za baobab, the Big cistern baobab, which was hollowed out for water storage. This specimen, which consists of 4 fused stems, was found to be 250 years old.

 7. Stephan Woodborne, Patience Gandiwa, Grant Hall, Adrian Patrut, Jemma Finch, A regional stable carbon isotope dendro-climatology from South African summer rainfall area, PLoS ONE, 2016, 11(7):e0159361. doi:10.1371/journal.pone.0159361.

Abstract. Previous carbon isotope analysis of four baobab (Adansonia digitata L.) trees from the Pafuri region of South Africa yielded a 1000-year proxy rainfall record. Here we present the analysis of five additional baobabs from the Mapungubwe region, approximately 200km to the west of Pafuri. The new Mapungubwe record correlates significantly with local rainfall, but there are significant differences when compared with the Pafuri record at certain times in the past. Both records confirm that the Medieval Warm Period was substantially wetter than present, and the Little Ice Age was the driest period in the last 1000 years. Dry conditions appear to persist in the Mapungubwe area until about AD 1840. The trees from Mapungubwe show sub-annual and super-annual rings, whereas two of the Pafuri trees showed annual growth ring structures. A possible reason for this may be that the Mapungubwe region is drier than Pafuri and episodic growth corresponds to rainfall events rather than continuous growth through the rainy season. It may be linked to the recently identified baobab species, Adansonia kilima nov.. While acknowledging the differences between the Pafuri and Mapungubwe records, they are combined to provide a regional climate proxy record for the northern summer rainfall area of southern Africa.

8. Adrian Patrut, Laszlo Rakosy, Roxana T. Patrut, Ileana-Andreea Ratiu, Edit Forizs, Dragos Margineanu, Karl F. von Reden, Radiocarbon dating of a very old baobab from Savé Valley, Zimbabwe, Studia UBB Chemia, 2016, LXI, 4, 7-20.

Abstract. The article reports the AMS radiocarbon investigation results of the Humani Bedford baobab, an old African baobab from Savé Valley, Zimbabwe. Two wood samples were collected from the large inner cavity. Several segments were extracted from these samples and analysed by AMS (accelerator mass spectrometry) radiocarbon dating. We found that the age values of segments increase with the distance into the wood. This major anomaly is characteristic to multi-stemmed baobabs with a closed ring-shaped structure and a false cavity inside. The investigation of the Humani Bedford baobab evinced that the baobab consists of three fused stems. The fourth stem of the ring is missing. The oldest dated segment was found to have a radiocarbon date of 1655 ± 14 bp, which corresponds to a calibrated age of 1575 ± 30 yr. The dating results show that the stems which build the ring stopped growing toward the false cavity more than 600 yr ago. By considering the position of the oldest segment in the investigated stem, we concluded that the Humani Bedford baobab is around 1800 yr old. According to our dating results, the Humani Bedford baobab becomes the oldest living African baobab.

9. Adrian Patrut, Roxana T. Patrut, Laszlo Rakosy, Jenö Bodis, Daniel Lowy, Edit Forizs, Karl F. von Reden, African baobabs with double closed ring-shaped structure and two separate false cavities: Radiocarbon investigation of the baobab of Golconda Fort, Studia UBB Chemia, 2016, LXI, 4, 21-30.

Abstract. The article discloses the results of radiocarbon investigation of the baobab of Golconda Fort, Hyderābād, India, which is the largest African baobab outside Africa. Two wood samples were collected from the large inner cavity; of these we extracted several segments for AMS (accelerator mass spectrometry) radiocarbon dating. The oldest sample segment had a radiocarbon date of 342 ± 22 bp, which corresponds to a calibrated age of 430 ± 20 yr. We estimate that the oldest part of the baobab has an age of 475 ± 50 yr. The investigation of the baobab of Golconda Fort revealed that it consists of 6 + 2 fused stems. Six stems build two rings that close two distinct false cavities, while two additional stems are located outside the rings. We called this new type of architecture double closed ring-shaped structure with two separate false cavities.

10. Adrian Patrut, Stephan Woodborne, Karl F. von Reden, Grant Hall, Roxana T. Patrut, Laszlo Rakosy, Pascal Danthu, Jean-Michel Leong Pock-Tsy, Daniel A. Lowy, Dragos Margineanu, The growth stop phenomenon of baobabs (Adansonia spp.) indentified by radiocarbon dating, Radiocarbon, 2016, doi:10.1017/RDC.2016.92.

Abstract. The article reports the growth stop phenomenon, which was documented only for baobabs, i.e., for trees belonging to the Adansonia genus. The identification of growth stop was enabled by radiocarbon dating, which allows a complex investigation of samples collected from the trunk/stems of baobabs. In several cases, the outermost rings of baobabs, which were close to the bark, were found to be old, with ages of several hundreds of years, instead of being very young. Dating results of samples collected from 6 baobabs are presented. For multi-stemmed baobabs, the growth stop may occur only for one or several stems. We identified four factors that may induce the growth stop: (i) stress determined by severe climate conditions, (ii) old age, (iii) the need to keep a stable internal architecture and (iv) the collapse of stems that survive this trauma. Baobabs and their stems affected by growth stop may survive for several centuries, by continuing to produce leaves, flowers and fruits. This phenomenon was associated with the capacity of baobabs to store large amounts of water in their trunks/stems in the rainy season. This reservoir of water is used over the dry season and allows the trees to survive prolonged drought periods.