Periodicity of growth rings in Juniperus procera from Ethiopia inferred from crossdating and radiocarbon dating

Wils, Tommy H. G.; Robertson, Iain; Eshetu, Zewdu; Sass‐Klaassen, Ute; Koprowski, Marcin

doi:10.1016/j.dendro.2008.08.002

Cited by 49 publications

(55 citation statements)

References 36 publications

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“…From a map displaying the climate and rainfall patterns in Ethiopia and Eritrea (after EMA 1988;Wils et al 2009Wils et al , 2010a, it is evident that the lowlands experience hot and dry climates, whereas the highlands experience cool and wet climates (Fig. 1).…”

Section: Study Areamentioning

confidence: 99%

“…Vegetation consists of freestanding trees, mostly J. procera and some Podocarpus falcatus, and Fig. 1 Climate and rainfall patterns in Ethiopia and Eritrea (after EMA 1988;Wils et al 2009Wils et al , 2010a (Couralet et al 2005;Sass-Klaassen et al 2008a), and the Abernosa woodlands (R) (Gebrekirstos et al 2008) …”

Section: Study Areamentioning

confidence: 99%

“…Dezzeo et al 2003;Mozeto et al 1988;Norström et al 2005;Robertson et al 2004Robertson et al , 2006Wils et al 2009;Worbes and Junk 1989). In the Northern Hemisphere, the radiocarbon calibration curve displays a 'plateau' in the period AD 1650-1955, which limits the potential to obtain accurate radiocarbon dates during this period (Stuiver et al 1998).…”

Section: Introductionmentioning

confidence: 99%

“…ex Endlicher (African Pencil Cedar) has been complicated by irregular stem shape, sensitivity of growth ring formation to local conditions, and year-to-year variability in rainfall regime (Conway et al 1997(Conway et al , 1998Jacoby 1989;Wils et al 2009). Successful studies identified annual rings that could be crossdated in J. procera trees from southern Ethiopia (Couralet et al 2005(Couralet et al , 2007Sass-Klaassen et al 2008a).…”

Section: Introductionmentioning

confidence: 99%

“…Building on experience from Wils et al (2009), we develop a conceptual model to capture the crossdating process. We test the hypothesis that the crossdated growth rings are annual by radiocarbon dating.…”

Section: Introductionmentioning

confidence: 99%

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Crossdating Juniperus procera from North Gondar, Ethiopia

Wils

Robertson

Eshetu

et al. 2010

Trees

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The application of dendrochronology in (sub)tropical regions has been limited by the difficulty in finding trees with distinct annual rings that can be crossdated. Here, we report successful crossdating of Juniperus procera trees from North Gondar, Ethiopia. The trees form annual rings in response to a unimodal rainfall regime. The selection of mesic locations ensured that the trees did not respond to intra-seasonal weather anomalies. Crossdating was achieved by comparison of the wood anatomy directly on the surface of the core samples and purpose-adapted skeleton plotting. Wood-anatomical anomalies, such as false and indistinct rings, were regarded as potentially replicated features and used in crossdating. COFECHA yielded site-specific mean series inter-correlations between 0.52 and 0.59. AMS radiocarbon dating during the bomb era indicated that dating uncertainty is ±1 year.

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Section: Study Areamentioning

confidence: 99%

Section: Study Areamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Crossdating Juniperus procera from North Gondar, Ethiopia

Wils

Robertson

Eshetu

et al. 2010

Trees

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Nonannual tree rings in a climate‐sensitive Prioria copaifera chronology in the Atrato River, Colombia

Herrera‐Ramírez

Andreu‐Hayles

Valle

et al. 2017

Ecology and Evolution

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In temperate climates, tree growth dormancy usually ensures the annual nature of tree rings, but in tropical environments, determination of annual periodicity can be more complex. The purposes of the work are as follows: (1) to generate a reliable tree‐ring width chronology for Prioria copaifera Griseb. (Leguminoceae), a tropical tree species dwelling in the Atrato River floodplains, Colombia; (2) to assess the climate signal recorded by the tree‐ring records; and (3) to validate the annual periodicity of the tree rings using independent methods. We used standard dendrochronological procedures to generate the P. copaifera tree‐ring chronology. We used Pearson correlations to evaluate the relationship of the chronology with the meteorological records, climate regional indices, and gridded precipitation/sea surface temperature products. We also evaluated 24 high‐precision 14C measurements spread over a range of preselected tree rings, with assigned calendar years by dendrochronological techniques, before and after the bomb spike in order to validate the annual nature of the tree rings. The tree‐ring width chronology was statistically reliable, and it correlated significantly with local records of annual and October–December (OND) streamflow and precipitation across the upper river watershed (positive), and OND temperature (negative). It was also significantly related to the Oceanic Niño Index, Pacific Decadal Oscillation, and the Southern Oscillation Index, as well as sea surface temperatures over the Caribbean and the Pacific region. However, 14C high‐precision measurements over the tree rings demonstrated offsets of up to 40 years that indicate that P. copaifera can produce more than one ring in certain years. Results derived from the strongest climate–growth relationship during the most recent years of the record suggest that the climatic signal reported may be due to the presence of annual rings in some of those trees in recent years. Our study alerts about the risk of applying dendrochronology in species with challenging anatomical features defining tree rings, commonly found in the tropics, without an independent validation of annual periodicity of tree rings. High‐precision 14C measurements in multiple trees are a useful method to validate the identification of annual tree rings.

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Effects of flow alteration on Apple‐ring Acacia (Faidherbia albida) stands, Middle Zambezi floodplains, Zimbabwe

et al. 2014

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The impounding of the Zambezi River by Kariba dam has regulated the river discharge of the Middle Zambezi river. This has been implicated in the failure of regeneration of Faidherbia albida in the downstream flood plain. This study aimed (1) to assess the effect of the altered flow regime of the river on the establishment and growth of F. albida on the Middle Zambezi floodplain and islands and (2) to test the potential of dendrochronology in detecting the age and long-term growth rates of F. albida in response to flow regime.Results indicated an uneven age distribution of F. albida stands on relatively 'new islands', dominated by young trees, while the floodplain and the 'old island' exhibited an even-aged stand but with a lack of regeneration, and a dying-off of older trees. The lack of F. albida establishment on the floodplain was linked to the decreased occurrence of flooding events, associated with a decrease in alluvial deposits, soil moisture and groundwater recharge. These effects may be enhanced by impact from browsers on regeneration of trees. Tree-ring analyses revealed the presence of distinct annual growth rings in F. albida and the applicability of dendrochronology for estimating F. albida population dynamics. The trees on the 'new islands' are younger and grow faster than those on the floodplain. Lack of competition and possible favourable moisture conditions suggest beneficial conditions for establishment and growth of the trees on the islands.

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Periodicity of growth rings in Juniperus procera from Ethiopia inferred from crossdating and radiocarbon dating

Cited by 49 publications

References 36 publications

Crossdating Juniperus procera from North Gondar, Ethiopia

Crossdating Juniperus procera from North Gondar, Ethiopia

Nonannual tree rings in a climate‐sensitive Prioria copaifera chronology in the Atrato River, Colombia

Effects of flow alteration on Apple‐ring Acacia (Faidherbia albida) stands, Middle Zambezi floodplains, Zimbabwe

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