Sap rise in spring

Gunnar Fridborg Gunnar.Fridborg at
Wed Oct 2 02:08:50 EST 1996

Another observation:

In the park around the main buildning of  Uppsala University they cut off
some branches of a birch  a few meters above the ground. This was done in
early spring. I passed the tree one or two weeks later when  winter had
come back temporarily with several degrees below zero. From the cut
surfaces big icicles were hanging and only from there. I took a picture
for educational purposes and we use to discuss the phenomenon in my
classes. Our explanation is frozen sap  and root pressure. I tasted one
icicles but it wasn=B4t sweet. Silly enough I didn=B4t take one with me to
analyze it further.

Gunnar, Uppsala

Gunnar Fridborg
Associate Prof, Lecturer, Director      Docent, Univ lektor, Studierektor
of Education
Department of Physiological Botany      Inst for fysiologisk botanik
Uppsala University                      Uppsala universitet
Villav=E6gen 6  S 752 36 Uppsala Sweden   Villav=E6gen 6  752 36 Uppsala
Phone +46 18 182820                     Tel 018 182820
=46ax   +46 18 559885                     Fax 018 559885
E-mail  Gunnar.Fridborg at

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