Philip J. Burton said he would be curious about different perspectives on
exotics around the world. To prompt discussion he asked about radiata pine
and some other named species.
The record of radiata pine in Australia, New Zealand and Chile is (in my
opinion) one of overwhelminig sucess! In all three countries large forest
utilisation industries are based on man made plantations of the species. If
you ask "what about conservation values?" then the clearest case is New
Zealand where the Government owned native forests have been vested in a
Department of Conservation and are scarcely used at all for production of
wood products. This was only possible because the plantations of radiata
pine now produce wood in excess of that country's needs and it became clear
that the native forests could be withdrawn from the process of wood
production. (Although because the wood they are capable of producing has
properties that are different from radiata pine a case could be made for
continued production.) The case is less clear in Australia where more wood
is harvested from native forests than from plantations of radiata pine. In
recent years large areas of potentially (wood) productive Australian native
forest have been given reserve status of some form or another and (again my
opinion) I would argue that this would not have happened to the same extent
if there had been no plantations of radiata pine to turn out the wood. As
David Norton said not all exotic species have been an unqualified success.
Pinus contorta has spread widely in the high dry county in both the North
and South Islands of NZ. This spread does indeed change the landscape, but
that begs a whole series of other questions. The way in which it changes
the apperance of the landscape is to make it look more like one of those
northern hemisphere countries that are famed for their picturesque mountain
views; say Switzerland or Austria, countries usually famed for their
natural beauty. I know some people that genuinely think the view of pine on
the slopes is OK. Certainly there will be some protection from erosion from
the tree crop. Why is it so good when these things occur as a result of
"natural" forces and so wrong if we create them by our own efforts using
our best technology including exotic species? (I am speaking generally here
of course. The spread of Lodge Pole pine in NZ's high country was not a
result of anyones best technology, it was a lack of appreciation of how
aggressive a coloniser the species is.)
The question Philip Burton has posed (ie exotics good or bad ?) is a very
complex one and to answer it you have to establish some criteria on which
you can form a judgement and declare a point of view. Some people just
don't like exotics. Here in Canberra the "man-made" capital of Australia
some people advocate the boycott of the city's annual spring garden
festival because it is based around beautiful tulip beds (originally a gift
of the Netherlands Government); just because they are exotic. The whole
city of Canberra has been transformed from a near tree-less plain to the
"Bush Capital" by the extensive and thoughtful planting of exotic tree
species although some suburbs (as it happens the including the one I live
in) were established in native forest that was carefully retained and these
have a distinct beauty of their own. The emotional preference for native
vegetation is hard to justify in unemotional terms; my exotic is your
native, is "nature" really so wonderful that the deal she gave each country
is the absolute best that could be done and to add another ingredient will
detroy some magic balance. If we look past forestry we see some very
spectacular sucesses for exotics: for Australia, horses, sheep and cows,
sugar cane, pineapple and wheat to name a few quickly - and rabbits, cane
toads and blackberry to name a few equally spectacular failures.
In my course of Timber Management I devote a lecture on the subjects of
exotics, monocultures and the likelihood of disease disasters etc. This
year one of my better students came to ask some questions afterwards and
told me that that was one of my poorest lectures. When I asked why he said
I had presented no firm conclusion and left the whole subject hanging in
the air. I my opinion I did a good job, this a subject on which it is just
not possible to make catagorical judgements for all times and places and
those who do ----- shouldn't. Ryde James
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Ryde James | Forestry/Science
Tel: (61+6)249-4330 | Australian National University
Fax: (61+6)249-0746 | Canberra, ACT 0200
|
___________________________________________________________________________
email: Ryde.james@anu.edu.au
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