Trees can die of hunger, as well as thirst, when they succumb to drought, a Tasmanian scientist has found.
Dr Patrick Mitchell, of the CSIRO, has discovered that drought affects two different parts of a tree’s life support system, which can lead to the tree’s demise.
“We previously thought that trees die when their plumbing system collapses. My research shows that a tree can potentially starve to death from a lack of stored sugars,” says Patrick.
“Understanding how trees respond to drought is fundamental to predicting which species will be most at risk from climate change and how much carbon they will be able to absorb from the atmosphere into the future,” he says.
As part of his research, Patrick imposed drought conditions on some common forest species and tracked the changes in key attributes of their life-support system. The study showed that different tree species have different ways of coping with drought.
“We found that the eucalypt species squander their dwindling water supply quickly and eventually die from thirst. The more conservative pine species studied, survived longer by reducing water loss, but used up its sugar reserves in the process,” he says.
Drought can affect the health of forests across the globe and recent episodes of widespread tree die-off in Australia and overseas highlight the need for understanding how and when trees die.
“This work shows that both the tree species and the type of drought it encounters can determine survival,” Patrick says.
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