I love the beautiful fall foliage on the east coast of Canada and the U.S.A. Do the leaves begin colouring in Canada first and then in Vermont, NY state and a bit later in Pennslyvania etc. or do the leaves colour in Canada and the U.S. all at the same time ?

Brainy Blonde

As summer ends and autumn comes, the days get shorter and shorter. This is how the trees 'know' to begin getting ready for winter. http://www.sciencemadesimple.com/leaves.html So, if the trees are in the same time zone they should be changing at the same time! LOL!!! I've lived here for 12 years and every fall when I am out and about, I always say I am going to take some photographs. This year the camera is in the glove compartment!!! They say The Cabot Trail in Cape Breton is the best place to see them in my part of the world. I'll make it up there one day. Sep 30 02, 1:04 PM

Autumn

I think temperature also encourages the leaves to do their magic. So the colder places change first. Sep 30 02, 5:05 PM

sibbu

The colour change is triggered by the colder temperatures, which are difficult to accurately predict, but it change earlier in the north, say about mid Sept in Canada around Ottawa, to late Sept. in southern parts of Canada like the Laurentian Mountains around Montreal or in the Toronto/Niagara Falls area. It would be getting more colourful around early to mid October in the New England area (say Vermont) and late October in Virginia. Surf the web for fall colour reports by the US Forestry service. Oct 01 02, 5:47 AM

Brainy Blonde

The colour change is not triggered by temperature, but by the lack of light. Deciduous trees need light to go through the process of photosynthesis. This process produces chlorophyll, which makes the leaves green. Not enough daylight, no chlorophyll. No chlorophyll, no green leaves. It is explained in simple terms at the website I posted above. Oct 03 02, 6:39 PM