WAKE UP, FORESTRY FOLKS!
Based on the membership of the Society of American Foresters
and the Ecological Society of America, foresters outnumber
ecologists 3 to 1. A similar ratio between foresters and
ecologists probably exists in other countries (except those in
the Sahara desert).
On the other hand, the number of daily messages on the
ecology network is at least 10 times greater than the number on
this one. Even more important is the quality of exchange. On the
ecological net, lively discussions and debates are ongoing.
Advice and jokes are swapped. Spontaneous arguments and thoughts
are shared. All this makes a striking contrast to the activity on
this net.
Because I am a 100% forester by vocation, training, and
employment, I can indulge in self-criticism. Are we as sleepy and
dull as forests seem to the uninitiated? Why don't we use this
miracle, e-mail, more productively and imaginatively?
Some ecologists, like ourselves, work with forests, though
in science departments. Yet, we are different. At least, I am.
The everyday barrage of mail from ecologists undermined my self-
esteem. On the other hand, I simply tired of their hyperactivity.
I recently unsubscribed to their net and returned to the quiet of
this one. If I am looking for quiet, I probably should not make
waves.
Still, some vitality would not hurt our net. To start with,
I suggest that we share preprints of interesting papers. I have
just finished, together with Fedor Semevski of Russia, writing a
paper entitled: "The pipe model theory: boring truth or a
fruitful mistake?" Below is the abstract and the discussion
section of the paper.
The point is not only to exchange papers but to provide
criticism and discussion as well. I would greatly appreciate your
comments on the papers.
This paper PIPE.TXT (in WordPerfect 5.1) as well as several others still
unpublished or recently appeared papers can be obtained by using
FTP. It is simple. Type at a prompt:
FTP 192.112.26.10
When you get the prompt for username, type:
anonymous
When you get the ftp prompt type:
cd zeide
Then since the files in this directory are in WordPerfect 5.1, type:
binary
You can then type "ls" or "dir" to get the list of available files.
To get a file type:
get [file name]
End the session by typing:
bye
Looking forward to your papers and comments.
THE PIPE MODEL THEORY:
BORING TRUTH OR A FRUITFUL MISTAKE?
Fedor Semevski and Boris Zeide
ABSTRACT
A bold hypothesis proposed by Shinozaki et al. (1964a, b)
under the name 'the pipe model theory' is presently a leading
model widely used in studies of tree structure, stem form, and
photosynthate allocation. The good thing about this hypothesis is
that it allows one to make many precise and testable predictions.
The bad thing is that these predictions as well as the main
assumption of the model contradict empirical evidence. The
experimental results presented in this paper are supported by
ecological, physiological, and historical evidence.
DISCUSSION
There is no doubt that since the stem conducts water to
foliage, some relationship between conducting area and foliage
mass or surface area must exist. This proposition does not
necessarily involve stem diameter. The principal function of the
stem is to support the crown. It was repeatedly shown that
diameter is determined primarily by mechanical load (caused by
the forces of weight or wind) (Larson 1963, Assmann 1970). When
the stem is large enough for this purpose, water conduction is
not a problem. Pipes run inside the Empire State Building, but it
is likely that its form was determined by considerations other
than pipe size.
The pipe model theory is simple, highly testable, and bold.
It is bold because it ignores accepted terminology, history, and
knowledge of tree morphology and physiology. Given its widespread
recognition, the shortcomings enumerated in this paper make the
pipe model theory even more fascinating. The importance of this
theory goes beyond establishing a spurious relationship between
stem diameter and foliage mass. Despite its faults, the pipe
model theory has provided a strong, although misguided, impetus
to the development of a whole branch of forest science dealing
with the study of tree structure. In a way, this investigation is
an expression of our appreciation of the theory.
This investigation afforded certain clarity to the empirical
validity of the pipe model theory. However, a larger question
remains unsolved. "Pluralism" of falsity and truth must not be
tolerated. It is an insult to the elementary principles of
science that makes the entire enterprise ridiculous. Yet, for
thirty years we have closed our eyes to these obvious
discrepancies with reality. The pipe model theory has been
praised, analyzed, applied, modified, tested, retested, and even
criticized, but no one noticed that the emperor has no clothes.
Does our attitude betray our lack of vision or indifference to
the truth?
Boris Zeide
School of Forestry, University of Arkansas
Monticello, AR 71656. USA
Phone: 501-460-1648. Internet: zeide@uamont.edu
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