When’s it coming? What’s it going to
be like?
Once again we’re asking Plumas County area
botanists and amateur botanists for a prediction
on this year’s fall color show. With such a late
spring and record snowfall during this year of
2011, leaf-peepers are wondering what that might
mean for this season’s fall foliage show.
 Naturalist,
educator, and photographer/blogger Joe Willis
(at left) weighed in:
“I’d say the spring, at this point, will have
little to do with fall phenomena except the
ground is a bit moister than average. The
temperature fluctuations and
cloud cover over the next few weeks, along with
the predictably shorter days, have more to do
with fall colors. I think we'll have a great
fall, partly because the broadleaf trees and
shrubs look healthier now.
 Plumas
National Forest District Botanist James Belsher-Howe
(right), is usually hesitant to make a
prediction on yearly color because there are so
many variables.
“The best is warm sunny days and cool nights,”
says Belsher-Howe. “ And not too cold. I don’t
think rain is necessarily bad. It was good thing
those big storms came in early enough, when
everything still in place. The leaves weathered
the blow.”
The botanist says the long term weather
prediction shows an equal chance of being colder
than normal AND warmer than normal. “So if it’s
not really hot, not really cold, not really wet,
and not really dry … that’s a good thing,”
Belsher-Howe muses.
While Belsher-Howe believes loss of daylight is
the major factor for changing leaves, and that
leaves still fall roughly the same time each
year, the intensity of colors can vary based on
weather.
“The reds can vary for all sorts of reasons.
Sometimes you have the oaks that turn red
although usually they’re yellow/orange. The reds
can also be influenced by the availability soil
nutrients,” he says.
Belsher-Howe agrees with Willis about the
broad-leaf trees. “I think that maples look
healthier than we’ve had in years,” he notes.
“And the cottonwoods seem like they have
something going on.. they seem to be starting
earlier.”
He also predicts leaf-peepers may find some
late-blooming wildflowers along with fall color.
When’s the peak? Each year, there are
some leaf-peepers who swear the fall foliage is
earlier than the year before (which we attribute
to aging and perception.)
The peak varies by species and elevation, and
throughout the forest it doesn’t happen all at
once. But for the past 13 years, the Visitors
Bureau has declared “peak” once the majority of
the foliage is considered at 100 percent. That
date has ranged from Oct. 15 to Oct. 27. Yet,
the foliage actually begins in late September
and can last through the second week of
November.
Why do leaves change color?
Shorter periods of daylight and variations in
temperature are the cues for deciduous
(leaf-shedding) plants to prepare for winter.
They begin to shut down their food-making
process (photosynthesis) and the production of
the green pigment chlorophyll. The plants
attempt to store up their chemicals by taking
out sugars and chlorophyll from their leaves.
This slowing allows yellow and gold pigments
(called carotenoids) to slowly emerge – which
have been there all along but are masked by
chlorophyll. Red pigment (called anthocyanin),
unlike the others, is not attached to the leaf
cells, but is produced by sugars in the leaf
veins, which are trapped when veins are closed
during the fall. The intensity of the red
pigment varies depending on the sugar
concentration and acidity in the cell sap, and
the amount of sunlight the
leaves receive. The best combination for
producing intense autumn colors is dry, sunny
days followed by cool (not freezing) dry nights.
When fall weather is cloudy and rainy, and the
nights warm, the color is usually less intense.
What the plants can’t store, they must deal with
as waste. They form a special layer of cells
that severs the tissues supporting the leaves at
the branch, causing the leaves to drop.
The yearly process doesn’t happen overnight, and
unpredictable weather makes each fall foliage
season unique. Varying microclimates among
ridges and valleys generally make for a long
fall color season in Plumas County, with “peaks”
occurring at different times in different areas.
The best time to spot the most color, however,
is usually the third week of October.
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