Why Do Leaves Change Color in the Fall?
It’s that time of year again! If you live in the Northern Hemisphere in a temperate zone (like over 50% of the world’s population¹) then some of the leaves around you are probably changing colors. This season-defining event is known for being both beautiful and the cause of a lot of additional yard work. Bring out the rakes and leaf bags! As it turns out, this common phenomenon serves an important evolutionary purpose.
I live in beautiful Boulder, Colorado. While this town is known for its amazing natural scenery, the leaves are not quite as dramatic as they are in some parts of the world. Here, the main attraction are the aspen trees. They grow in clusters, and their leaves switch quite rapidly into a shocking yellow before falling off. At first, this phenomenon might seem counterintuitive. Why would trees go through all the work of growing leaves each year only to get rid of them and start over? Additionally, why do some leaves change to different colors than others?
