Why do Leaves change colour?

I have found this really interesting web page on why the leaves change colour through the seasons, below I have posted the information which I feel is quite relevant to the colour picking for the seasons, its a bit of a long read but if you don't know why its really interesting. (http://www.colourlovers.com/blog/2007/09/23/seasonal-color-inspiration-autumn/)

Autumn is a time when the sun's angle changes, things become cooler, and all of those beautiful leaves earn a fiery glow before falling. The spectacle is so popular that people plan entire vacations around the possibility of seeing the fall foliage. Where I live, the leaves are just beginning their change. Here, the most change comes in October, but we've had some early starters. Changing to red, orange, yellow, yellow-green, and even purple is all part of a process that allows the deciduous trees to survive even a harsh winter. What makes leaves green is chlorophyll. During the growing season (chiefly summer), leaves are so dominated by the green of chlorophyll that all other pigments within the leaf are masked. When the cold sets in, and the sun withdraws, the trees begin a withdrawal process of their own. The sugars that are produced by chlorophyll are drawn back into the tree as this will be its sustenance, and the chlorophyll itself is reduced in number. A layer of cork forms between the branch and the leaf, which eventually will allow the leaf to fall. During the change from chlorophyll-abundance and chlorophyll-absence, colour change will occur. Chlorophyll is not the only pigment in present in leaves. Carotenoids are neighbours to the green pigment, and visually surface during the withdrawal phase. Carotenoids are what cause yellow, orange, brown, and the colors between, while Anthocyanins bring red and purples. Carotenoids commonly give characteristic colour to many living things like carrots, corn, canaries, and daffodils, as well as egg yolks, rutabagas, buttercups, and bananas. As far as trees go, the radiant yellows and oranges are more specifically seen on hickory, ash, maple, yellow poplar, aspen, birch, black cherry, sycamore, cottonwood, sassafras, and alder trees. Anthocyanins are not always present in the leaf. They develop in the sap of the leaves in late summer during the breakdown of sugars. The level of light and phosphates in the leaf also hold an influence on the level of Anthocyanins present. Higher phosphate levels are an integral part of the plants sugar breakdown, as in well as the production of Anthocyanins. The brighter the light during this time, the greater the production of anthocyanins and the more brilliant the resulting color display. When the days of autumn are bright and cool, and the nights are chilly but not freezing, the brightest colorations usually develop. They can also be seen in early spring, often coloring the edges of young leaves as they burst from buds. Anthocyanins can be seen in cranberries, red apples, blueberries, cherries, strawberries, and plums. In trees, their fire is most notably found in the maple, oak, sourwood, sweetgum, dogwood, tupelo, black gum and persimmon trees.