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

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 Nino‐Southern Oscillation (ENSO) phenomenon We have explored the potential of kauri tor 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‐kaun 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‐kaun 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‐kaun 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