When lichens are first discovered on a tree, there is usually a great concern that they will damage the tree in some way. Read here whether tree lichens need to be removed.

In a nutshell

  • there are many different types of lichen
  • Symbiotic creatures made up of fungi and algae or bacteria
  • completely harmless to trees
  • Tree lichens indicate air quality, some lichen species have therefore become very rare
  • can be removed with a brush

identify tree lichens

Although lichens on trees come in different colors, they all look so alike that it's hard to confuse them with anything else. Usually they are green, yellow-green or blue-grey-green. Lichens are not independent plants, but living communities, which cannot be seen with the naked eye.

Notice: Lichens can get very old. 100 years and more are not uncommon.

A fungus forms the basis of the lichen, it adheres to the substrate, ensures stability and supplies the community with water and minerals. The alga or cyanobacteria adheres to the fungus, benefits from its water intake and performs the photosynthesis of the community.

Common lichen species

Plum lichen/oakmoss (Evernia prunastri, left), common yellow lichen (Xanthoria parietina, right)
  • Evernia prunastri, preference for sloes and plum trees
  • Common yellow lichen (Xanthotia parietina) on bark and rocks in agricultural areas
  • Key lichen (Parmelia), last lichen species in heavily air-polluted areas
  • Sculptor's lichen (Graphis scripta) on linden, mountain ash or hazelnut

Differences to mushrooms

Real tree fungi don't just stick to the tree, their root system penetrates the wood and destroys it. Also, many fungi are putrefactive, so they are actually harmful. Only the fruiting body is visible, which has different colors depending on the type of mushroom, but rarely green. Tree fungi are often very hard and difficult to detach from the substrate, the fruit bodies are often much larger and, above all, thicker than lichens.

lichens on trees

Since tree lichens appear to particularly like to colonize older, weakened trees, they are considered pests. This assumption is incorrect, however, as they do not penetrate the tree and therefore do not deprive it of nutrients or damage it in any way. Some lichens can settle better on weakened trees because they have fewer antibodies in the bark. Since lichens occur frequently in locations that are comfortable for them, the corresponding trees can be literally overgrown by them. This is particularly visible in winter when the tree has no leaves.

remove lichen

tree lichen do not and should not be removed, especially not for purely aesthetic reasons. Some lichen species have now become rare due to pollution and require any habitat they can find. There is also protected species.

One reason for removal is general trunk care, which involves loosening loose pieces of bark from the tree to prevent pests from nesting underneath. A hard brush is usually sufficient for this.

In some cases, tree lichens even have a protective function.

Notice: Lichens even protect trees because they prevent harmful organisms from colonizing their place on the bark.

Tree Lichens and Air Quality

Lichens are considered an indicator of air quality because they can only absorb their nutrients from the air. The better the air, the more diverse the lichen species that can be found in an area. Conversely, this means that lichens are completely absent in locations with very poor air quality.

frequently asked Questions

What are lichens used for?

In barren areas, lichens serve as food, for example reindeer lichen for reindeer, which they can still find under the snow. They also serve as nesting material for birds and even humans use lichens in different areas.

Do you have to use chemicals?

This is completely unnecessary against the lichen and harmful to the environment, even if the lichen grows on stones.

What happens when the lichen buds overgrow?

Then it can actually lead to growth disorders in the tree. In this case, it makes sense to remove the lichen around the buds.

Category:

Garden plants