What Causes the Leaves to Change Colour in Fall?

Fall colours in Collingwood and Blue Mountain
The gradual decrease in sunlight in the Fall is what causes the leaves to change colour. In the Summer, the tree benefit from longer days and longer periods of sunlight. The green chlorophyll in the leaves produces sugar and exchanges carbon dioxide for oxygen. Carotene and xanthophylls, whcih eventually show up as orange and yellow, are always there, but they remain idle whle the chlorophyll is working. As the amount of sunlight wanes in mid to late August, the tree’s natural programming tells it to prepare for winter. A layer of cells grows over the intake in the root structure and forces the tree to slow its consumption of water. The lack of water sends the chlorophyll into hibernation, and as the green goes dormant, the carotene and xanthophylls become visible.

This entry was posted in Nature. Bookmark the permalink.

Comments are closed.

3 Day Forcast

partlycloudySaturday
Sun and clouds mixed. A stray shower or thunderstorm is possible. High around 20C. Winds NW at 10 to 15 km/h.
POP:20
chancetstormsSunday
Variable clouds with scattered thunderstorms. High 17C. Winds W at 10 to 15 km/h. Chance of rain 60%.
POP:60

chancerainSunday
Partly cloudy in the morning. Increasing clouds with periods of showers later in the day. High 17C. Winds light and variable. Chance of rain 60%.
POP:60