[TriLUG] Really OT: maples turning yellow

[Aaron Joyner]

I'm not in the mountains proper, but at least in the foothills, in
Lenoir, Sawmills, Granite Falls, etc... nothing has started to change,
yet.  I doubt the temperature / water-shedding theory, as it's my
recollection that for most leafy chlorophyll-based plant life, they
tend to wilt their leaves to adjust the sunlight on the leaves in
extreme temperature (because photosynthesis is less efficient at
higher temperatures), rather than shed them.  Take that with the grain
of salt that I heard a news report about a journal article about that
topic, many months ago.

Aaron S. Joyner


On Wed, Aug 3, 2011 at 11:49 AM, Joseph Mack NA3T <jmack at wm7d.net> wrote:
> This perhaps be answered by people living in or visiting the Blue Ridge
> area...
>
> In the last 2 weeks, with the temps in the high 90's or above, the leaves on
> the maples on the American Tobacco Trail, where I ride my bicycle, have
> started to turn yellow and fall. None of the other trees are doing this.
>
> Since it doesn't get cold here till Oct, the trees still have 2 months for
> growth. It's hard to imagine that right now any living thing would be
> preparing for winter. Two reasons why maples might be shedding leaves.
>
> o the leaves are triggered by photoperiod. We're getting a 14hr day now. If
> maples are genetically optimised for living at 50-60degN, then a 14hr day
> would occur in early Sep.
>
> http://en.wikipedia.org/wiki/File:Hours_of_daylight_vs_latitude_vs_day_of_year.png
>
> when it would be getting quite cold.
>
> o the maples, not being designed for heat, are shedding leaves to conserve
> water, and are not responding to photoperiod. In this case maples at the
> same latitude, but in cooler or wetter environs, eg higher elevation (the
> mountains to the west or in VA) would not be shedding leaves.
>
> Anyone know if in the mountains, maples started turning yellow 2 weeks ago?
>
> Joe
> --
> Joseph Mack NA3T EME(B,D), FM05lw North Carolina
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