Why are trees still green in late October?

It'salmost November, but many parts of Ottawa are looking decidedly summery.

While there are splashes of fall colourhere and there, and some trees have started to shed their foliage,plenty of others remaingreen.

Why, you ask?

The days are surely getting shorter, which is normally a signal for trees to shutdown for the winter and drop theirleaves.

But it's been a very warm fall. The average daily high temperature so far this October is 18.9 Cwell above the normal of only 12.7 C. Basically, some trees have been "tricked" into staying green far past their normal time.

Let's hope we don't get an early snowstorm, becausethe result of heavy snow on leaf-laden branches would be devastating.