Fall Tree Facts

Why do leaves change color in the fall?

When the days become shorter, chlorophyll (the chemical in trees that causes the green color in leaves) dies off and other chemicals become the main source of color revealing different pigments or “fall color.”

Why do trees drop their leaves in the fall?

In the fall, trees begin to grow a layer of scar tissue at the bottom of each leaf stem weakening the connection as it walls off the stem and hardens in preparation for colder weather. The leaves will then let go due to stiff winds and gravity.

What is dormancy & what is happening to trees when they go dormant?

Dormancy is the shutting down of trees as they exit the growing season resembling a plant hibernation. Trees enter their dormant stage in later summer or early fall and remain dormant until new buds form in the spring. Trees can also go dormant during droughts and/or if they are stressed from heat to protect themselves.

During dormancy, trees slow down their growth and metabolism to survive the unfavorable conditions of winter. They will shift their priorities from growing leaves to sending nutrients to their roots for storage over the winter months. Sap flows and acts as an antifreeze to prevent damage over the cold months. If possible, late fall is an excellent time to plant trees as they do not need to contend with setbacks due to the summer heat as they are acclimating.