A revised little ice age chronology of the Franz Josef Glacier, Westland, New Zealand

A reassessed Little Ice Age chronology of the Franz Josef Glacier is presented. Diameter at breast height of 1340 southern rata (Metrosideros umbellata) and kamahi (Weinmannia racemosa) was measured within 50,150-m(2) quadrats in the Waiho Valley. Age-size relationships based on 60 tree-ring counts and associated diameter at breast height measurements were constructed, although the unknown shape of growth curves beyond the realm of tree-ring data rendered extrapolation unreliable. Thus, the revised chronology is interpreted from mapped tree-ring counts and measured diameter at breast height of the largest rata and kamahi within moraine limits and trimlines to determine the minimum time elapsed since deglaciation. The Franz Josef Glacier's Little Ice Age (LIA) maximum culminated before AD 1600, when it terminated c. 4.5 km down-valley of its 2001 position. Subsequent, but lesser magnitude, re-advances culminated by c. AD 1600 and 1800. This pattern is strongly corroborated by other New Zealand proxy climate data. Evidence from this reassessment provides increasing support for an earlier LIA maximum of the Franz Josef Glacier than is often cited.