How Leaves Work

Have you ever wondered what brings out the fall color of leaves? To find the answer, you have to understand how trees and leaves work. Trees need to eat, just like you and I do. But their food is not fertilizer any more than a multivitamin is food for us. Carbohydrates and sugars are the tree’s real foods. Leaves produce carbohydrates and sugars through a process known as photosynthesis. Start your recipe for photosynthesis with chlorophyll, a green substance contained within a plant’s chloroplast. Stir in a little energy from sunlight, mix in some water and carbon dioxide, and you’ve whipped up a batch of carbohydrates and sugars—tree food. Chlorophyll is broken down during photosynthesis, but new chlorophyll is produced to replace it during the growing season.

How Leaves Change Color

As summer transitions to fall and the weather cools, the flow of green chlorophyll is slowly cut off as the veins in the leaf close, especially at night. The lack of green chlorophyll reveals the true color pigments of the leaf that were hidden during the time of energy production.

Why do Trees Lose Their Leaves in the Fall?

Why do trees lose their leaves in the fall? One reason is to keep the tree from being damaged by heavy snow and ice clinging to leaves. Another is the loss of water that takes place during the process of transpiration. (Transpiration is the movement of water from the root system, up the trunk and branches, and out through little openings, called stomata, in the leaves.) Transpiration is important during energy production. But as sunlight becomes less available during the winter, photosynthesis stops. To conserve  resources, trees stop the loss of water as much as possible.

Benefits of Fallen Leaves

As leaves fall to the ground, they form a protective layer over the tree’s root system that regulates soil temperature, traps moisture, and reduces compaction. As the leaves decay, vital nutrients are added to the soil and absorbed by the root system, completing a highly efficient natural cycle. Of course, we humans sometimes disrupt those benefits; we break out our rakes and spend hours of hard work removing every last leaf so that we can have the cleanest yard in the neighborhood. We experience some benefits, such as exercise, and the kids get to jump in the big pile of leaves. But raking is not good for the trees. If you let the leaves stay in place, you can help the process of decay and of recycling nutrients back into the soil. Instead of raking, go over the leaves with a mulching lawn mower a couple times, or throw them through a mulching chipper if you happen to have one handy. Chopping the leaves helps them decay much faster, which brings their benefits into play sooner.

Identifying Trees Through Their Leaves

Leaves can help you identify trees. Start with a leaf’s general shape and color, and look at its margins. Are the margins smooth, serrated, lobed, or serrated and lobed? Their appearance on the stem serves as a clue. They can be alternate or opposite along the stem, or they might be simple or compound. If you are interested in identifying trees and other plants, you can download a plant identifying app on your smartphone or tablet. When you find a tree you want to identify, open the app, take a photo and see what it is. Here is a list of some of the more popular plant apps. So enjoy the colors of fall this autumn, but with a better understanding of the wonder of leaves. You can simply admire them from a distance, use them for enhancing the soil, or play in a big pile of them. Help your trees get ready for winter. Contact Growing Earth Tree Care today to schedule an appointment with a certified arborist.