In the clear - thirsty natives still grow
A quest to discover how native trees respond to climate change is showing their capacity to conserve their resources, using less water as they continue to grow.
The knowledge gained from the project will underpin environmental and catchment management strategies for the 21st century.
The Hawkesbury Forest Experiment, conducted by a team of researchers including Craig Barton from Industry & Investment NSW, and Jann Conroy and Burhan Amiji from the University of Western Sydney (front page picture), is already revealing how native forests will react to climate change.
It’s a world first, recently described to the International Union of Forest Research Organizations (IUFRO).
The researchers are growing eucalyptus trees in Star Trek-like chambers, subjecting them to elevated carbon dioxide (CO2) levels and drought conditions.
Three years in, with phase two just starting, research scientist, Dr Craig Barton, says the team is uncovering promising data about the potential of forests to adapt.
“Because these chambers encase the whole tree canopy, we are able to study the trees’ water, carbon and nutrient cycles and crucially, the way they all interact under different conditions,” he said.
“Most trees can acclimatise to changes in their environment.
“But what we are finding is that these trees, growing in soils with low-nutrient status, typical of most Australian conditions, are actually adjusting how they use their resources and becoming more water efficient.
“This means they continue to grow as before but use less water.”
Typically, increased CO2 in the atmosphere triggers enhanced growth in plants, but in this case, the eucalypts seem to focus their efforts on water efficiency rather than increased growth rates.
Water loss is much lower for trees in the chambers with elevated CO2.
“The potential implications here are that our native forests might survive drought better in future,” Dr Barton said.
“In an area with low rainfall, the plants tend to use all of the available water and then batten down the hatches till the next rain event.
“Increased water-use efficiency under elevated atmospheric CO2 in these environments may result in higher productivity but no change in the amount of water used by the forest.”
At the start of phase two, brand new batches of seedlings have just been planted in upgraded chambers, thanks to a funding grant from the Education Investment Fund.
These new and improved chambers are enabling scientists to look at the combined effects of both rising temperature and rising CO2 concentration on whole tree growth and physiological processes of Australian native species under Australian conditions.
Dr Barton has just presented an overview to a conference of international scientists in Melbourne.
The IUFRO conference in mid-October adopted the theme “Canopy processes in a changing climate”.
IUFRO is a global network for forest science co-operation that unites more than 15,000 scientists in almost 700 member organisations in more than 110 countries, and is a member of the International Council for Science.
The Hawkesbury Forest Experiment is a collaborative effort, based at the University of Western Sydney’s Hawkesbury campus, with researchers from all the major Sydney universities and the Swedish University of Agricultural Sciences.
Previously funded by the Australian Greenhouse Office, a recent funding grant from the federal Department of Agriculture, Fisheries and Forestry takes the project forward another 12 months.
The researchers are now hoping funding will be extended, so the trees can grow to maturity and provide insights to improve land managers’ ability to manage natural forests and woodlands.
Contact Craig Barton, West Pennant Hills, 0417 461 698, firstname.lastname@example.org