The area under plantations in northern Australia has increased
rapidly since the mid-1990s, much of it on soils and into climates
that are outside historical plantation management experience. The
estate now covers a wide range of latitudes and many challenging
geographic conditions: extreme weather conditions of cyclonic
winds, heavy rainfall and flooding in the north; and risks of
droughts and heavy frosts in the south. Predicting rotation-length
outcomes under these circumstances is difficult, and extrapolating
from experience in one region with a particular set of geographic
conditions to another region with different geographic conditions
is unwise. In many cases, the physiological and disturbance events
that determine the outcomes are very different from those in
southern and Mediterranean climates where experience is
rich.
To this challenge is added the prospect of climate
change—predicted to manifest itself in creating drier, hotter
environments where plantations are grown and, perhaps more
importantly, in creating greater annual climatic variability and
more extreme events or seasons.
This project focuses on developing sufficient understanding of
the physiological and environmental determinants of growth and
profitable plantation development in our northern climate. This
knowledge will be used to develop not only expected plantation
performance but also used to try to analyse the probable impact on
plantation success of low-frequency climatic events such as frost,
drought or cyclone damage.
The project is achieving these goals by focusing on a few key
and typical plantation species: Eucalyptus pellita (grown
in plantations in the humid tropics of the Northern Territory and
north Queensland and the South Pacific), and E. dunnii and
Corymbia citriodora subsp. variegata (both
planted extensively in the subtropics of New South Wales,
Queensland and internationally).
This understanding will be used to parameterise, and if
necessary structurally modify, an existing physiology-based model,
CABALA (Carbon Balance). CABALA
links carbon, water and nitrogen fluxes and pools to predict growth
under changed environmental conditions and is particularly well
suited to scenario modelling to estimate variability and risk once
site and species parameterisation has been undertaken. The
knowledge gained from applying this approach to CABALA can be
translated rapidly to other process-based models.
The leader of Project 1.4 is Dr Mila
Bristow (DEEDI, Qld).
