NetNews Usenet Archive 1993 #3/NN_1993_3.iso/spool/sci/skeptic/22989

Internet Message Format | 1993-01-28 | 2.6 KB

Path: sparky!uunet!tdat!tools3!swf
From: [e-mail] (Stan Friesen)
Newsgroups: sci.skeptic
Subject: Re: does this sound right?
Message-ID: <[e-mail]>
Date: 28 Jan 93 17:29:05 GMT
References: <1993Jan23.4286.31987@dosgate> <[e-mail]>
Sender: [e-mail]
Distribution: sci
Organization: NCR Teradata Database Business Unit
Lines: 41

In article <[e-mail]>, [e-mail] (Stephen F. Schaffner) writes:
|>     I have no references, but I have seen reports that suggest that it's
|> actually quite difficult to restore rain forest once it's been cut down, at
|> least on a time scale that's of any interest to us ("forever" is of course
|> hyperbole).

Yep, that is so.  In fact no area where rain forest is known to have been cut
has yet completely recovered to its original state.  (The rain forests of Africa
are quite odd - they seem to be entirely secondary forest - no primary forest at
all - guess why?)

|> These were just news reports (NY Times?), and I didn't pay much
|> attention to them, so you'd be advised to check them out yourself if you're
|> really interested.  My recollection is that attempts to restore small areas
|> of rain forest (in Costa Rica?  or was that another story about rain forests?)
|> showed that the forest soil was too poor in nutrients to start a forest
|> growing there again; most of the nutrients had been located in the forest
|> canopy, and were lost when it was removed.

This is well known.  It has been determined in many ways over the years.
Due to the high rain fall any nutrients in the soil are *quickly* leached out.
Thus tropical soils are acutally amoung the most sterile in the world. A rain
forest can maintain itself only by rapid *recycling* of the nutrients it
contains.  Thus one gets extremely rapid decay, and very shallow roots to
immediately reabsorb the released nutrients.

Now, if a cleared area is allowed to start regrowing in about a year, a new
forest *will* come in - just one that has far fewer species of trees in it,
and one that is less complex in internal structure.

There is also another major problem with tropical soils on cleared land.
The main mineral compponent is the same mineral as is found in china clay
- you know, those fine china dishes in your cabinet.  Guess what ahppens to
it when it is exposed to the hot sun for any length of time?

That's right - it gets fired - voila a giant ceramic plate shaped like a field.

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