Age determination of large live trees with inner cavities: radiocarbon dating of Platland tree, a giant African baobab
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For large trees without a continuous sequence of growth rings in their trunk, such as the African baobab (Adansonia digitata L.), the only accurate method for age determination is radiocarbon dating. As of today, this method was limited to dating samples collected from the remains of dead specimens.
Our research extends significantly the dating of such trees to large live specimens with inner cavities. The new approach is based on collecting samples from the cavities and their subsequent radiocarbon dating.
The giant two-stemmed Platland tree, also known as Sunland baobab, was investigated by using this new approach. AMS radiocarbon dates of the oldest sample segments originating from the two inner cavities indicate that the large stem I (364.5 m3) is 750 ± 75 years old, while the much smaller stem II (136.7 m3) has 1,060 ± 75 years. Results also show that stem I is still growing very fast, while the older stem II slowed down consistently its growth over the past 250 years. The complete mapping of Platland tree determined an overall wood volume of 501.2 m3.
Dating results demonstrate that the size–age relation cannot be used for estimating accurately the age of African baobabs.
KeywordsAdansonia digitata Radiocarbon dating Age determination Growth rate Accelerator mass spectrometry
This work was fully funded by the Romanian Authority CNCSIS-UEFISCDI under grant PN II-IDEI 2354, Nr. 1092. AMS radiocarbon dating at the NOSAMS Facility is supported by the U.S. National Science Foundation under Cooperative Agreement OCE-0753487. We would like to thank Heather and Doug van Heerden, the owners of Sunland Nursery, for granting permission for on-site investigation and also for sampling the Platland tree.
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