It's very beautiful to watch the forest during fall, when the colours slowly transition from deep green to this deep fiery red.
This colour change is a natural part of the fall process, where the tree (or bush) tries to recover and recycle as many nutrients as possible from the leaves, before they fall off, and the more effort the tree will put into this process the redder the leaves will get.
The colour changes occur, when the tree start to break down the green chlorophyll in the leaves and then redistributes the nutients contained there to their trunk and roots - this keeps them going throughout the winter, when the sunlight is sparse.
