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Re: TT: RE: Fall color peaking in Baltimore
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> The forestry crews seem to keep the Ailanthus out pretty well (or is
> that a function of such broad diversity?)
It may actually be a function of creating the conditions in which all the
other trees survive. I rarely find ailanthus in rich soil which is
watered regularly. It, rather seems to like very thin (if any) soil in
places which experience both drought and temporary flooding conditions.
> > Apologies for making this so long. Looking at the remaining leaves
> this time of year, it's obvious that bright sun hitting them ac-
> celerates (amplifies) their coloration. Somehow the trees have a
> 'memory' of the current climatic conditions (to borrow a computer
> term). So what I'm wondering is, where are these 'memories' recorded?
> My naive guess is in the leaves themselves, that the biology of one
> single leaf triggers when it changes color and drops, independent of
> its peers. Otherwise the entire tree, or at least large sections
> of it, would 'fall' all at the same time, which does not appear to
> be the case (for most resident deciduous species).
>
In a related unscientifically studied finding of mine, I have noticed that
branches of trees which are next to street lights will hold onto their
leaves far longer (weeks) than branches which are otherwise unilluminated.
I do not know if this is because of the extended light cycle, or the
because of the heat thrown off the lamps.
Ah, what wonderful observations from a city.
Lisa
New York City
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