High Latitude Forests Dying

truffler1635 at my-deja.com truffler1635 at my-deja.com
Sat Nov 18 07:29:22 EST 2000

In article <3A15BB6D.3284C8D at daviesand.com>,
  Karl Davies <karl at daviesand.com> wrote:
> http://news.bbc.co.uk/hi/english/world/americas/newsid_1024000/1024585.stm
> Almost all Alaska is
> covered by a layer of
> permanently frozen
> ground. But this
> permafrost is thawing in the higher
> temperatures, steadily destroying millions of
> acres of spruce and birch trees, and with it
> the habitat for much of the state's wildlife.
> Scientists from the University of Alaska in
> Fairbanks are working in the wide Tanana
> Valley in the centre of Alaska, where the
> forest is turning into a watery fenland. The
> valley was once covered with birch trees. If
> the warmer climate persists, they are all
> expected to be dead by the end of the
> century, unable to survive in standing water.
> Vicious cycle
> It's not only Alaska's huge forests that are
> drowning in the swamps created by this great
> thaw. Forests on once permanently-frozen
> ground across vast tracts of Russia, Canada
> and Northern Europe are also in jeopardy.
> Dr Glenn Juday, a forest specialist with the
> University of Alaska in Fairbanks, says that as
> the forests die, they are feeding the process
> of global warming in a terrible vicious cycle.
> Rotting trees are producing millions of tonnes
> of carbon dioxide, and of methane, one of the
> most potent greenhouse gases of all.
> "The great forests of the north are a
> storehouse of carbon", says Dr Juday, "and the
> warmer weather causes them to give off
> carbon dioxide and methane. Those are
> contributing to the warming itself. It's a
> positive feedback mechanism - the more it
> warms the more these processes are putting
> these gases back into the atmosphere."
What is described may be a simple replacement of species as warming
occurs. It may lead to more aspen groves which can, in certain cases,
survive quite a bit of water near the roots. Many poplar species will
likely come into the area as well. And since aspen and poplar are fast-
growing trees compared to spruce (and some birch sps) the net result may
be _greater_ carbon sequestration in higher latitudes. In other words, it
_could_ be beneficial instead of disasterous.

Climate modeling seems to indicate a movement northward of more rapid-
growing trees with global warming. What effects these new species may
have on global warming of the future is still unknown.

Daniel B. Wheeler

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