How and why does autumn palette of colors happen?

In Colombia, we do not have seasons, so we do not have the change of color on our trees leaves or the gorgeous magic of different flowers in spring, but we do have a nice weather and colorful flowers year round.

I have been living in United States for 8 years and the changing fall foliage never fails to surprise and delight me. Every year I wonder how and why does autumn palette of colors happen? I have found 2 articles that explain this magnificent process; one explains the process in a simple manner and the other one a little bit more technical.

http://www.sciencemadesimple.com/leaves.html

http://www.na.fs.fed.us/fhp/pubs/leaves/leaves.shtm

Enjoy the beautiful and colorful pictures from Dahlonega at North Georgia Mountains that I took 2 weeks ago.

[slideshow]