I asserted:

Deciduous trees don't need light. [in winter]

David declaimed:

That's not entirely accurate I don't think Jim. Certainly the
deciduous tree
lacks the food synthesizing structures (leaves) in winter, but
light also
plays a role in other functions of the tree's growth (or lack
of
growth)(photomorphogenic response?). It's my understanding that
photoreceptors other than chloroplasts trigger such diverse
actions as
initial leaf-out and flowering. These photoreceptors-- most
notably and the
only ones I know even a tiny amount about being phytochromes
and
cryptochromes-- respond to blue or red ends of the light
spectrum.


And I rebut:

Well, there are an awfully large group of 'nawthrun' bonsaiests
who tell me they store their trees in unheated, unlighted
garages, and others who keep them in cold frames that get buried
in snow (which does, allow some tinty amount of filtered light
through it is it's not too deep, I suppose). I neither know of
nor have heard hints of, anything in a tree that is not
green-stemmed (acacia, etc.) that would indicate that deciduous
trees have any need for light. Most green-stemmed trees and
shrubs are tropical, semi-tropical or evergreeen. I have not, of
course, heard everything there is to hear. ;-)

David again:

Peter Adams has long held the anecdotal notion that Chinese
Elm, even when
dormant, appreciate bright light or else really fine
ramification will be
shed in spring. I'm not aware of any research with regard to
Ulmus, but it's
possible that they are especially sensitive to drastic changes
in those
wavelengths of light and react accordingly.


And me (a bit less certainly):

Chinese elms often act as if they are evergreen and, in fact ARE
evergreen in the southern part of their range, but they are
(mostly) deciduous in the north (outdoors). However, they may,
in fact have chloroplasts under their bark -- at least in young
stems.

This tree in question here is a Zelkova, which does not.

Peter Adams, for all of his exemplary skill as a bonsaiest, is,
if I recall right, trained as an artist, and is not a biologist.

Jim Lewis - - Tallahassee, FL - Our life is
frittered away by detail . . . . Simplify! Simplify. -- Henry
David Thoreau - Walden

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