Age and growth rate dynamics of an old African baobab determined by radiocarbon dating

Author Posting. © Arizona Board of Regents on behalf of the University of Arizona, 2010. This article is posted here by permission of Dept. of Geosciences, University of Arizona for personal use, not for redistribution. The definitive version was published in Radiocarbon 52 (2010): 727-734.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.This material is based on work supported by a grant from the Romanian National University Research Council (PN II - IDEI 2354 Nr. 1092) and by US National Science Foundation under Cooperative Agreement OCE-022828996

Radiocarbon dating of African baobabs with two false cavities : the investigation of Luna tree

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.The Romanian Ministry of National Education CNCS-UEFISCDI under grant PN-IIID- PCE-2013-76.http://chem.ubbcluj.ro/~studiachemiaam2016Mammal Research InstituteZoology and Entomolog