The Spirit of Mawson - Australasian Antarctic Expedition 2013 - 2014

Australasian Antarctic Expedition

Tree growth

The New Zealand subantarctic islands are home to the southernmost-growing trees in the southwest Pacific. In sheltered locations, some Dracophyllum have been shown to reach more than four metres in height, with their growth hypothesised to be controlled by temperature. By measuring the thickness of annual tree rings, Dracophyllum provides the possibility of developing a natural weather record back to the 19th century.

The research program

  1. On the AAE 2013-2014 we set out south to find how subantarctic trees respond to changing temperature.
  2. On the AAE 2013-2014 we wanted to try and understand whether temperature-driven tree-lines on Campbell Island were higher in the past and were these associated with warmer summer temperatures?
  3. On the AAE 2013-2014 we wanted to discover whether the Southern Ocean played a role in historic changes in the carbon cycle.

Research Papers

Intensification of Southern Hemisphere Westerly Winds 2000 to 1000 Years Ago: Evidence from the Subantarctic Auckland and Campbell Islands (50-52 ̊S)

Turney, C.S.M., McGlone, M., Palmer, J., Fogwill, C., Hogg, A., Lipson, M., Thomas, Z., Wilmshurst, J., Fenwick, P., Jones, R., Hones, B. and Clark, G.

On the subantarctic islands, peat exposures show Dracophyllum once grew above present day tree line. Here we find there was a major collapse in the altitudinal limit of growth between approximately 2000 and 1000 years ago suggesting westerly winds were stronger at this time.