Why Leaves Change Colour

Autumn is often referred to as the “picture perfect” season

as splashes of colour fill trees across the country.

The fall colour season has already begun in the province of Ontario

with parts of northern and eastern regions reporting a 5-10% change.

Pockets of vibrant reds and yellow are beginning to show,

but green currently remains dominant across much of the country.

Travel and Tourism officials say colours usually begin to peak

by the end of September and into October.

Why do the Leaves Change Colour?

“It's all about photosynthesis, how a tree feeds itself,”

says The Weather Network's Chris St. Clair.

“The leaves take in water and carbon dioxide and when you add in the sun,

the leaf cooks up glucose, a kind of sugar that helps a tree grow. When this is happening, chlorophyll is being created that gives leaves their green colour and when the days become shorter and cooler, it signals the tree to stop creating food and chlorophyll.”

St. Clair adds that the lack of chlorophyll is what reveals the tree's

natural yellow and orange colour and the red is a sign of trapped glucose.

Tree stress can affect whether the fall show will be spectacular or not. Things like drought, extreme temperatures and air pollution can make the leaves dull.

Buckles

(a cartoon by David Gilbert in an August issue of The Spec)

...shows his dog asleep in the fenced yard...stretched out on his tummy

with chin resting on its folded paws...

having a “dog dream”

Summer fun is all but done.

The leaves in the breeze

in all the trees

will soon be old and gone.

Warmth will stay but soon go away,

as lower sinks the sun.

Birds make way and go astray

grouped together as one.

South in the sky, they fly so high

catching the wind in their wings.

Soon they'll find a paradise

to perch and rest and sing.

The sky will grey, the green will fade

and the ground will be covered in white;

so inside we'll stay with fire to aid

while the day grows shorter than night.

Why things change is all a wonder;

yet these thoughts don't concern me...

because today I'll lie in the cool, green grass

and soak in the end of summer.

Merle Baird-Kerr

written September 16, 2011