Journal of the Royal Society of New Zealand abstracts

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Dendroclimatic interpretation of tree-rings in Agathis australis (kauri): 2. Evidence of a significant relationship with ENSO

Anthony Fowler¹, Jonathan Palmer², Jim Salinger³, John Ogden⁴

¹Department of Geography, University of Auckland, Auckland, New Zealand
²Department of Ecology and Entomology, Lincoln University, Canterbury, New Zealand
³National Institute of Water and Atmospheric Research, Auckland, New Zealand
⁴School of Environmental and Marine Science, University of Auckland, New Zealand

Part 1 of this investigation (Buckley et al. 2000) found consistent significant correlations between tree growth and climate for nine New Zealand kauri tree-ring chronology sites. The nature of these correlations suggests that Agathis australis (kauri) may carry a useful signal of the El Niño-Southern Oscillation (ENSO) phenomenon. We have explored the potential of kauri for ENSO reconstruction through statistical analysis of the relationship between the Southern Oscillation Index (SOI) and the tree-ring indices previously derived. Results showed a consistent SOI-kauri growth relationship for eight of the nine sites. A significant negative correlation was found between kauri growth and concurrent seasonal mean SOI, and a positive correlation with the seasonal mean SOI recorded over the preceding two years. The former is consistent with a hypothesised ENSO-kauri growth model, but the two-year lag suggests an additional relationship, perhaps associated with kauri phenology. Decadal-scale variability was evident in the strength of the SOI-kauri growth relationships, particularly in autumn (March-May) and winter (June-August). Comparison of SOI and extreme kauri growth years indicated general consistency in the growth response to ENSO, but also identified some anomalies, suggesting that kauri ring-width is an imperfect ENSO proxy. However, combined with the spatial scale at which ENSO operates, and the known variability of links with regional climates, we conclude that kauri growth-rings could provide a useful ENSO proxy, particularly within the context of multi-proxy spatially distributed studies.

Keywords  Tree-rings; Agathis australis; kauri; climate change; palaeoclimatology; dendroclimatology; ENSO; El Niño; Southern Oscillation; SOI; New Zealand

(c) Journal of The Royal Society of New Zealand,

Volume 30, Number 3, September 2000, pp 277-292

PDF file of entire paper: medium quality (1012K); (scanned from paper original: notes about this process)

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