Andrea Stockton, staff writer
October 17, 2011 — Colours are becoming more vibrant across the country. Some areas have already reached peak levels. Do you track the fall colours?
Autumn is often referred to as the “picture perfect” season as splashes of colour fill trees across the country.
The fall colour season is in effect across Canada, and in many sections of Ontario the colours have reached, or have passed, “peak” levels. Places like Kenora, Thunder Bay, Fort Frances, Sault Ste Marie, Sudbury and Algonquin Park are now past their peak. Colours are peaking around Barrie, Collingwood, Muskoka and Ottawa. There has been a 70 per cent colour change in Niagara, 50 per cent change in the Toronto Area, and about 30 per cent change in the Essex area.
Meanwhile, colours continue to shine in parts of Quebec and the Maritimes. Foliage in most parts of Prince Edward Island are beginning to reach its peak, although some trees lost their leaves last week due to recent wet and windy weather. Still, several areas are displaying large patches of colour.
Travel and tourism officials across the country say colours usually show by the end of September and peak into October, so this is a great time to head out and see them for yourself.
Why do the leaves change colour?
“Temperature plays a factor in the coloration of trees, but the most important factor is called the photo period, or the length of daylight,” says horticulturalist Bob Osbourne of Cornhill, NB.
“The shortening of the number of hours of daylight is the trigger for trees to start shutting down. A cork-like layer forms between the leaf stem and the branch, which will eventually fall off and it also protects the tree from any kind of fungal or bacterial infection. As it shuts down, it begins to stop water and nutrients from coming into the leaf and the chlorophyll dies.”
Osbourne says this phenomenon is what allows us to see the various pigments that have been there all along, but are only visible now because of the lack of green.
Stress is a big factor in coloration. It may be a matter of too much or too little water, or other nutritional factors. You can spot a stressed tree by its leaves, which change color before the others.
Tree stress can affect whether the fall show will be sensational or not. Things like drought, extreme temperatures and air pollution can make the leaves dull.
“The most famous of all the trees is the Sugar Maple,” adds Osbourne, “with its combination of orange, yellow, and sometimes red. One of the most spectacular of the trees is the native Red Maple with its vivid red color. These are the trees we most associate with fall.”
Wondering how the colours will progress in your area this year?
If you have a favourite spot to see the fall colours, tell us on The Weather Network's Facebook page.
You can also help us tell this story by sharing your photos. Upload them easily to our Your Weather Gallery.
With files from Kimberly Lamontagne and Lyndsay Morrison