School of Plant Science, University of Tasmania
Received the Australian Flora Foundation Young Scientist Award for his talk at ESA2010, the Ecological Society of Australia Conference on 6 - 10 December 2010 at the Manning Clark Centre, ANU, Canberra.
Age and growth of a Tasmanian temperate old-growth forest stand dominated by Eucalyptus regnans, the world's tallest angiosperm
S.W. Wood1, Q. Hua2, K.J. Allen1, D.M.J.S. Bowman1
1School of Plant Science, Private Bag 55, University of Tasmania, Hobart, 7001, Australia.
2Australian Nuclear Science and Technology Organisation, PMB1, Menai, NSW 2234, Australia.
Temperate old-growth forests contain some of the highest above-ground
stores of carbon. The ecology of many temperate forests is dominated
by episodic disturbance, such as high intensity fire. Eucalyptus regnans
forests are particularly carbon dense and are adapted to infrequent catastrophic
fires. Understanding the growth and longevity of old-growth trees is
crucial to understanding the carbon balance and fire regimes of these
forests. In an old-growth E. regnans stand in Tasmania we used dendrochronological
techniques and radiocarbon dating to determine the age and stem growth
of E. regnans and Phyllocladus aspleniifolius, an understorey rainforest
conifer. Our analysis revealed that an even-aged cohort of E. regnans
and P. aspleniifolius established in 1490-1510AD, apparently after a
stand replacing fire. Growth rates of E. regnans were rapid compared
to P. aspleniifolius. That the longevity of E. regnans is > 500 years
challenges the 350-450 year timeframe proposed by the traditional model
of succession from eucalypt to rainforest. These forests not only store
vast amounts of carbon, but also maintain high carbon densities for a
long period of time. Estimates of the capacity of temperate forests to
store carbon should consider past fire regimes and increased fire frequencies
associated with climate change.