Saturday, 29 December 2012

Jarrah forests collapsing due to dry climate

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Jarrah forest_deathsObservational research has found that trees growing near areas of shallow soil are the ones that are dying. Image: Courtesy George MatusickA DRYING climate may be contributing to the decline of Western Australia’s Jarrah forests.

Researchers are witnessing a continuing pattern of tree deaths every year as WA experiences lower rainfall.

Murdoch University PhD Candidate Emma Steel has received over $4,000 from the Graduate Women (WA) Open Scholarship to research how drying climate is affecting local Jarrah forests.

In conjunction with Centre of Excellence for Climate Change, Woodland and Forest Health, Ms Steel is researching Jarrah forests at five sites in Monadnocks Conservation Park and says the forests as we know them will gradually change as a result of drying climate and extreme drought events.

Observational research has found that trees growing near areas of shallow soil are the ones that are dying.

“When there are occurrences of extreme heat and drought, the shallower soils run out of moisture before the deeper soils, which is why the trees are dying there in those areas,” she says.

Ms Steel has expressed concern that a continuing pattern of tree deaths every year due to lower rainfall will cause gradual change to the Jarrah forest.

“It’s a long term issue. You see this mass collapse of the canopies in that area, and they do [recover] to a certain degree,” she says.

“But because the trees are so stressed by the drying climate, other things are killing them as well—they’re more susceptible to pathogens.

“I really hope that we don’t get huge areas dying, but it could happen. If we get a few years in a row with really low rainfall there could be mass death of areas.”

The research aims to create awareness that tree death is due to drought, so the forest can be managed differently.

“There’s got to be an implication in management of the forest somehow and we’ll get the information to look towards how it can be managed better in the future,” Ms Steel says.

“We can’t control the weather, so I think just being aware and not taking it for granted that our beautiful forest is going to be there forever as it is now.

“This scholarship allows me to look at soil depth and moisture holding capacity, which requires special equipment.

“I wouldn’t have been able to add this dimension to my research without the financial support.”

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