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From: wfi@unc.UUCP (William F. Ingogly)
Newsgroups: net.sf-lovers
Subject: Re: Silent Running and loss of oxygen
Message-ID: <12@unc.UUCP>
Date: Sat, 13-Apr-85 11:59:58 EST
Article-I.D.: unc.12
Posted: Sat Apr 13 11:59:58 1985
Date-Received: Mon, 15-Apr-85 05:31:31 EST
References: <topaz.1164>
Reply-To: wfi@unc.UUCP (William F. Ingogly)
Organization: CS Dept., U. of N. Carolina at Chapel Hill
Lines: 49
Summary: 


> Removing forests  will cause us to lose a lot of topsoil immediately and
> knock great gaping holes in the ecosystem in  other ways I'm sure  -- is
> there an ecologist out there who can elaborate for us?

I *almost* have an MS in environmental sciences (never finished my
thesis), so I think I can help out on this question. If you'd like to
read up on the science of ecology, try E. P. Odum's text (I can't
remember the title right now, unfortunately). 

Loss of the world's tropical forests would have several unfortunate 
consequences:

1. A large fraction of the world's animal and plant species live in 
   the tropics. Elimination of the tropical ecosystems would destroy
   a potentially valuable and little-understood gene pool. How many
   life-saving drugs have we already found in the tropics, for 
   example?

2. The lateritic soils found in the tropics are low in organic matter,
   and at least some of them turn rock-hard when exposed to the sun.
   Angkor Wat (sp?) was built with lateritic soils, and it's lasted
   for hundreds of years. If the overlying vegetable material is
   removed, the land beneath would make pretty good landing fields
   but would be good for little else. Loss of topsoil doesn't occur
   in the tropics, since there's little topsoil; virtually all 
   nutrients and organic matter are tied up in living organisms.

3. Evapotranspiration from the rain forests has an large impact on
   the world's weather systems, since tropical trees are incredibly
   efficient water pumps. I seem to recall that a rain forest puts
   nearly as much water back into the atmosphere as an open tract
   of water of equivalent size. The result of the removal of the
   world's tropical forests would probably be the desertification 
   of large tracts of land in the South American and African 
   continents, which would have unknown consequences for weather in
   the northern hemisphere. There's a vicious cycle involved here:
   less vegetation leads to less rainfall leads to less vegetation...


As I recall, loss of the world's temperate forests would have some
impact but nothing like the dire consequences of the rain forests'
destruction. Of course, a large amount of the system's nutrients and
organic matter is tied up in the temperate forest's soil, so erosion
renders the land useless for agriculture. It's been a number of years
since I studied environmental sciences, so I hope others can add to
this or patch the holes in my discussion.

                                          -- Bill Ingogly