Tree Talk| 2 min read

Why Do Lichens Grow On Trees?

Have you ever seen a tree whose bark is covered with these white and green colored, fuzzy little splotches?

Have you ever seen a tree whose bark is covered with these white and green colored, fuzzy little splotches? What you’re seeing is a lichen. Lichens grow on many different types of trees and, despite some popular beliefs, are not at all harmful to the tree. Some consider them unsightly, but the tree doesn’t mind.

What is a lichen?

A lichen is a truly unusual organism, in part because it isn’t just one organism. A lichen is a symbiotic organism comprised of an algae and a fungus. Symbiosis is when two or more organisms benefit from one another. In the case of the lichen, a fungus grows on a tree that collects moisture, and that moisture is exactly what the algae requires to live.

In return, the algae creates a byproduct that the fungus feeds off of. So the fungus provides the habitat and the algae provides the food.

Where do lichens grow?

There are a few mediums where lichens are able to grow. It is dependent upon where the fungus feels most at home. They can grow on trees as well as bricks, walls, rocks, roofs, and even on soil.

Why do lichens grow on trees?

Lichens grow on trees simply because the tree provides the fungus a good habitat on which to grow. The fungus sinks very shallow roots that grab onto the surface of whatever it is they happen to be attached to. This is why so many different places can be home to a lichen.

How can I get rid of lichens?

Lichens are not harmful to trees what-so-ever, but some do consider them to be unsightly. There are a few things you can do to get rid of them if that’s your desire. The first step you take should be to create an environment in which a lichen will have difficulty growing. They enjoy cool, damp places. So thinning the branches, thus allowing more sunlight and air to reach the trunk and branches of the tree, can result in a less hospitable habitat for a lichen.

There are chemicals you can use to remove lichens, but we do not recommend using these due to the environmental impact. If you want to get rid of lichens on your trees, you can simply take a brush and brush them off. A mild soap mixed with water can help prevent the lichen from growing back, but may not be necessary.

Otherwise, when it comes to lichens on your trees, there really isn’t anything to worry about! Lichens are just something else to love about trees.

Tree Talk

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