This is a sample of the byway color in past seasons.
Stay tuned for this year's color as it develops . . .
green leaf is green because of the presence of a group of pigments known as
When they are
abundant in the leaf’s cells, as they are during the growing season, the
green color dominates and masks out the colors of any other
pigments that may be present in the
the leaves of summer are characteristically green.
chlorophylls have a vital function; they capture some of the sun’s energy and
utilize it in the
manufacture of the plant’s food – simple sugars which are
produced from water and carbon dioxide.
sugars are the basis of the plant’s nourishment – the sole source of the
needed for growth and development.
their food-manufacturing process, the chlorophylls themselves break down and
thus are being
continually “used up.” During
the growing season, however, the plant replenishes the chlorophyll
so that the
supply remains high and the leaves stay green.
as autumn approaches, certain influences both inside and outside the plant cause
to be replaced at a slower rate than they are being used up.
During this period, with the total supply
of chlorophylls gradually
dwindling, the “masking” effect slowly fades away.
Then other pigments
that have been present (along with the chlorophylls)
in the cells all during the leaf’s life begin to show
These are the carotenoids; they give us colorations of yellow, brown,
orange, and the many
hues in between.
reds, the purples, and their blended combinations that decorate autumn foliage
come from another
group of pigments in the cells called anthocyanins.
These pigments are not present in the leaf throughout
the growing season
as are the carotenoids. They
develop in late summer in the sap of the cells of the
leaf, and this development
is the result of complex interactions of many influences – both inside and
outside the plant. Their formation
depends on the breakdown of sugars in the presence of bright light
as the level
of a certain chemical (phosphate) in the leaf is reduced.
in the fall, phosphate, along with the other chemicals and nutrients, moves out
of the leaf into the
stem of the plant. When
this happens, the sugar-breakdown process changes, leading to the production
of anthocyanin pigments. The brighter
the light during this period, the greater the production of
anthocyanins and the
more brilliant the resulting color display that we see.
When the days of autumn
are bright and cool, and the nights chilly but
not freezing, the brightest colorations usually develop.
temporarily color the edges of some of the very young leaves as they unfold from
in early spring. They also
give the familiar color to such common fruits as cranberries, red apples,
blueberries, cherries, strawberries, and plums.
our autumn forests, they show up vividly in the maples, oaks, sourwood,
sweetgum, dogwood, tupelo,
black gum, and persimmon.
These same pigments often combine with the carotenoids’ colors to give
the deeper orange, fiery reds, and bronzes typical of many hardwood species.
carotenoids occur, along with the chlorophyll pigments, in tiny structures –
called plastids – within
the cells of the leaves.
Sometimes they are in such abundance in the leaf that they give a plant
yellow-green color, even during the summer.
But usually we become aware of their presence for the
first time in
autumn, when the leaves begin to lose their chlorophyll.
are common in many living things, giving characteristic color to carrots, corn,
and daffodils, as well as egg yolks, rutabagas, buttercups, and
brilliant yellows and oranges tint the leaves of such hardwood species as
hickories, ash, maple,
yellow-poplar, aspen, birch, black cherry, sycamore,
cotton-wood, sassafras, and alder.
A MORE DETAILED ILLUSTRATION ON AUTUMN COLOR VISIT THE How
Leaves Change COLOR website.