CONTRIBUTED CONTENT: Leaf drop

Fall is here folks, and I think we can all officially say goodbye to wearing shorts for the year. While I will miss being able to walk to my truck in the morning in a T-shirt, and driving to work with my window down, I do have to admit that I love the changing of the seasons. 

Have you ever stopped to wonder what causes the leaves to turn color and fall from the trees? There is actually much more going on here than you may think. As summer comes to an end, the days gradually become shorter and the nights become longer. Trees are extremely sensitive to this change in daylight, and it helps them recognize that winter is approaching. Temperature, moisture availability, and stress can also influence the timing of fall color and leaf drop. This is why you may occasionally see a tree begin changing color much earlier than the trees around it. Drought, root problems, disease, insects, or other stresses can cause a tree to begin shutting down portions of its canopy earlier than it normally would. 

As fall approaches, the tree begins a remarkable process of preparing for winter. The green pigment in leaves, called chlorophyll, begins to break down. As the chlorophyll disappears, other pigments that were already present in the leaf become visible leaving the yellow and orange colors we see in many species. At the same time, the tree isn’t simply abandoning its leaves. It is actually recycling them. Throughout the growing season, leaves are valuable factories for the tree. They produce sugars through photosynthesis and contain nutrients the tree needs. As the growing season comes to an end, the tree begins reclaiming some of those nutrients and moving them back into its branches, trunk, and roots where they can be stored and used again next year. 

Hormones help coordinate this process. Changes in hormones such as auxin, ethylene, and abscisic acid contribute to the process of leaf senescence — the natural aging of the leaf — and eventually help initiate leaf separation. Near the base of the leaf stem, the tree begins forming a specialized abscission layer. As this layer develops, the connection between the leaf and the tree gradually weakens until the leaf eventually falls. 

It’s also worth remembering that not every tree follows the same schedule. Species differ in when they change color and drop their leaves, and even trees of the same species can behave differently depending on their location, health, available moisture, and exposure to sunlight. 

So, the next time you’re standing in a pile of leaves wondering why you have to rake them for the third time that week, take a moment to appreciate what you’re looking at. That pile of leaves represents the final stage of a carefully coordinated process that allows the tree to prepare for winter, conserve its resources, and start fresh again next spring. 

As always, for further quotes, questions, or consultations, give us a call today!

For more information on Grace Tree Service, check out our website at gracetreeservice.com.