How Do Trees Know When to Change Color?

Trees tend to change the color of their leaves at almost the same time every year. It’s an amazing spectacle that makes every fall season special. You may notice previously green leaves start to turn orange, bright red, and yellow.  

But where do these colors come from? And how do trees know when to change color? As seasoned tree service experts in Vero Beach, FL, we discuss the timing of leaf color changes and how it happens.  

Leaf Pigments  

The entire process of leaves changing colors starts inside the leaf.   

Color pallets need pigments, and the leaves of all trees generally contain chlorophyll, the most abundant green pigment with the capability to capture light energy from the sun and use it to convert carbon dioxide and water into sugars (a process called photosynthesis). 

Many trees contain other pigments as well. That said, leaves have four main types of pigments, including:  

• Chlorophyll (greens)  
• Carotenoids (oranges)  
• Anthocyanins (reds)  
• Xanthophylls (yellows)  

Reasons for Leaf Color Changes  

So, how do trees know when to change color? The short answer is that daylight length determines the timing.  

Leaves are green in the spring and summer because that’s when they make lots of chlorophyll. Light from the sun triggers the leaves to keep making more chlorophyll, but trees know how to adapt when environmental conditions change.  

As fall approaches and summer fades away, days start getting shorter, and the sun shines much less. This environmental change triggers the tree to start preparing for the next season, winter.  

Most trees become dormant and devise coping mechanisms during winter because the harsh conditions make it difficult for them to survive.   

How do they do that? They stop making more chlorophyll. With less sunlight in the winter, trees will slow down the production of chlorophyll as it starts to store food resources for the harsh weather.   

Once the tree stops producing chlorophyll, the green color starts to fade, unmasking the red, yellow, and orange pigments before the trees eventually fall.  

Weather also plays a critical role in the color change. In the fall, temperatures get colder, and it rains and snows more. Such temperature changes may play a role in how early the leaves change and how long they maintain their fall colors.  

Bottom Line  

Ultimately, perennial plants and trees must find ways to survive winter’s harsh temperatures. It’s some form of self-tree care. 

The timing of color changes in leaves helps them survive harsh winters and primarily depends on the duration of sunlight. While other environmental factors affect when leaves change color, such as temperature, food supply, and rainfall, none make a bigger impact than when days become shorter.  

Contact Your Local Tree Experts for a Free Quote  

Your trees deserve high-quality service from start to finish. Trust King Tree Management to deliver that and much more. We specialize in providing professional and comprehensive tree services, including:  

• Tree trimming and pruning  
• Tree removal  
• Certified arborist services  
• Stump grinding  

Call our tree professionals at (772) 633-1939 for answers to the question, “How do trees know when to change color?” or to learn the value of a tree health assessment.