Download The colours of autumn

Green
During the spring and summer months,
leaves are filled with green chlorophyll
which helps trees to harness the sunshine
and turn it into food.
The colours
of autumn
To survive the winter, most trees will shut
down to store their sugars. A cork-like
membrane develops between the branch
and the leaf stem, depriving the leaves
of nutrients and breaking down the
chlorophyll.
Yellow
The yellows of autumn leaves come
from xanthophyll pigments and can
be seen throughout autumn in a
variety of trees including birches,
beeches, ashes and field maples.
The yellow colour of egg yolks are
because of the xanthophyll in plant
products, eaten by the hens.
Autumn colours are influenced by the weather
due to the effect different conditions have
on the chemicals in the leaves. But how do
these chemicals give us autumn colours? The
Forestry Commission explains.
During summer leaves already contain most
of the colours of autumn, however they
are “covered up” by the dominant green
chlorophyll. Chlorophyll is the green pigment
in plants that harnesses energy from sunlight
to combine water and CO2 to create sugars
(plant food).
As the weather cools and the leaves start to
receive less sun, the tree realises that winter is
about to begin. Chlorophyll breaks down and
the new, colourful pigments takeover giving
us beautiful autumn displays.
#Autumnleafwatch
forestry.gov.uk/autumn
Forestry Commission
Woods & Forests
@ForestryCommEng
Red
The red colour is unlike other leaf
colours as it hasn’t always existed
in the leaf. The colour is caused by
anthrocyanin pigments which are
formed by a reaction between sugars
and certain proteins in cell sap.
If the sap is quite acidic, the pigments
impart a bright red colour. If the sap
is less acidic, then the resulting colour
is purple. Japanese maples produce
plenty of anthrocyanins and have
really bright red leaves.
Orange
Orange comes from beta
carotene – one of the most
common compounds in plants.
One of the best trees to see
carotene in action during autumn
is Sweet Chestnut. Carotene, as
its name suggests, is also the
chemical responsible for giving
carrots their unique colour.