Early Fall Leaf Colors in Colorado

Summer is starting to end, and days are getting shorter, but fall colors are beginning to appear before they should in Colorado. There are a few explanations as to why.

What usually causes leaves to change colors and fall?
Trees use cues from the environment to time when to produce and shed their leaves. The natural shortening of days and lengthening of nights is primarily what a tree uses to begin the process of slowing down photosynthesis and preparing itself for winter. Warm, sunny days followed by cool nights will also signal the tree to start this process.

Why are the leaves changing early?
A variety of factors can influence early leaf change in a tree. A cooler than normal late summer and early fall can signal the tree to start changing colors, even if the days aren’t short enough for it yet. Trees that have received too little/too much water can cause chlorophyll production to slow down which will initiate an early leaf drop. Newly transplanted trees are susceptible to early fall leaf drop due to transplant shock. Additionally, severe weather of any kind can stress or damage a tree to the point that leaves will either change early or drop off entirely.

Some tree species will naturally change and drop their leaves earlier than others, so knowing what tree you are looking at will help you determine if it is dropping its leaves early. For example, certain species of cottonwoods, willows, and aspens can start to change as early as late August to early September, but oaks will usually turn last, sometime in late October to early November. 

If you are unsure what is causing your tree to turn colors early, please feel free to reach out to our Bailey Tree ISA certified arborists. They can examine your tree and help you come up with a plan to make your tree happy and healthy again.