POTD: Views From the Pond #16

Views From the Pond #16
Bozeman, Montana

Years ago we planted a single aspen tree sapling next to our pond. It has grown to about 25 high over it’s life so far and we now have multiple new aspens that have sprung from its spreading roots. All these aspens came from that same first tree and grow close together in similar soil with similar moisture availability; so why is the the only one that turns red instead of the usual aspen yellow in the fall?