Towards a reconstruction of Blue Nile baseflow from Ethiopian tree rings

Wils, Tommy H. G.; Robertson, Iain; Eshetu, Zewdu; Koprowski, Marcin; Sass‐Klaassen, Ute; Touchan, Ramzi; Loader, Neil J.

doi:10.1177/0959683610365940

Cited by 39 publications

(35 citation statements)

References 86 publications

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“…Ring 42, provisionally dated to 1965, was most probably formed in 1964 or 1966, and ring 14, provisionally dated to 1993, was most probably formed in 1993 (Wils et al 2010a). It is clear from the radiocarbon dates that the crossdated growth rings of the J. procera trees from North Gondar are mostly annual in nature.…”

Section: Radiocarbon Datingmentioning

confidence: 81%

“…Details on the AMS radiocarbon dating of growth rings 14 and 42 from core M8A are given in Table 4 (Wils et al 2010a). Ring 42, provisionally dated to 1965, was most probably formed in 1964 or 1966, and ring 14, provisionally dated to 1993, was most probably formed in 1993 (Wils et al 2010a).…”

Section: Radiocarbon Datingmentioning

confidence: 99%

“…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%

“…Radiocarbon dating AMS radiocarbon dating was performed on growth rings 14 (provisional date AD 1993) and 42 (provisional date AD 1965) from a Gomia-Mariam tree core (M8A) at the 14 CHRONO Centre of Queen's University Belfast (Wils et al 2010a). Two atmospheric radiocarbon concentration datasets were used for calibration.…”

Section: Ring Boundary Detection Crossdating and Ring Width Measurementmentioning

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: Radiocarbon Datingmentioning

confidence: 81%

Section: Radiocarbon Datingmentioning

confidence: 99%

Section: Study Areamentioning

confidence: 99%

Section: Study Areamentioning

confidence: 99%

Section: Ring Boundary Detection Crossdating and Ring Width Measurementmentioning

confidence: 99%

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Crossdating Juniperus procera from North Gondar, Ethiopia

Wils

Robertson

Eshetu

et al. 2010

Trees

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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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Central England temperature since AD 1850: the potential of stable carbon isotopes in British oak trees to reconstruct past summer temperatures

Young

Bale

Loader

et al. 2012

J Quaternary Science

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In regions with seasonal temperate climatic regimes, tree growth is rarely controlled by any single environmental factor. As a consequence, the development of robust palaeoclimate reconstructions has proved challenging. Tree-ring stable carbon isotope ratios (d 13 C), however, are controlled primarily by photosynthetic rate, not by net growth. Therefore, at sites where climatic controls on tree-ring growth are not strongly expressed, a robust (isotopic) palaeoclimate signal may still potentially be preserved. This hypothesis was tested using a 160-year record of d 13 C measured from the pooled latewood cellulose of six Quercus petraea L. (sessile oak) trees from Allt Lan-las in West Wales, UK. Raw d 13 C values were corrected for changes in the isotopic ratio of atmospheric carbon dioxide and for changes in the behaviour of trees due to the increasing availability of atmospheric CO 2 since AD 1850. Strong correlations with local summer temperature and sunshine are reported, and also with the Central England Temperature record over the full length of the isotopic chronology (AD 1850-2010) (r ¼ 0.69, P < 0.001). We conclude that treering stable isotopes can be used to extract strong palaeoclimate signals even from oak trees growing in a temperate maritime climate. This demonstrates the potential for extracting robust palaeoclimatic information from the very long and well-replicated oak chronologies which have been developed in western and central Europe primarily for dating rather than palaeoclimatic research purposes.

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Towards a reconstruction of Blue Nile baseflow from Ethiopian tree rings

Cited by 39 publications

References 86 publications

Crossdating Juniperus procera from North Gondar, Ethiopia

Crossdating Juniperus procera from North Gondar, Ethiopia

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

Central England temperature since AD 1850: the potential of stable carbon isotopes in British oak trees to reconstruct past summer temperatures

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