Journal of the Royal Society of New Zealand abstracts
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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