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By PENNY FANNIN SCIENCE REPORTER The Age, Australia
Changing
global weather patterns appear to have caused the treeline
around Mount Hotham and Falls Creek to creep uphill.
Research
by scientists at La Trobe University has found that during
the past 25 years the treeline in alpine Victoria has moved
up to 40 metres.
John
Morgan, an alpine plant ecologist in the university's school
of botany, said snow gums in the sub-alpine forest had been
stable for many years but new trees had become established
in the past quarter-century.
"We
are seeing trees growing where they have never grown before,"
he said. "Since 1975 something has happened that was
not going on in the past."
By a
process of deduction Dr Morgan has identified temperature
change as the most likely cause of the new plant growth.
"Cold
temperatures limit these trees and if they're now growing
in areas where previously they could not then it's because
it's not so cold."
Weather
records from the area showed that temperature had increased
and the length of the snow season had decreased.
Young
snow gums, which were growing in previously bare regions,
were healthy and some were up to eight metres high, he said.
"A
mean annual temperature change of one degree might have
been enough to let these things get through when they previously
could not."
Dr Morgan
does not believe his observations are just a local phenomenon
as they have been made at four sites around Mount Hotham
and two near Falls Creek.
In the
mid-1990s a survey of mountains in Germany showed that the
number of alpine plant species had fallen - one of the first
signs that biological systems responded to global warming.
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