Festive Earth Society - Direct Buy Mountain View

Many people have been asking us about why leaves change colours and why they fall from the tree.
Botanists who study leaves for a living explain that when the tree leaf first emerges in the spring, it already possesses a special layer of cells which will cut the leaf off in the fall. The layer is called the abscission layer - or, less scientifically, cutting layer.

The layer accomplishes two things. First it discards the leaf cleanly when the leaf is no longer of any use to the tree. Second, it forms a scab on the tree side of the cut, so that the tree does not lose precious water in the wintertime when water is very scarce.