Lichen is everywhere! On the bark of ornamental trees as on the trunks of fruit trees, or even on shrubs, in particular on old azaleas… Although it is harmless, one always has the impression that it parasitizes the plants on which it supports. We therefore often try to eliminate it, which is not necessarily a good idea! Explanations.
Do not confuse lichen and moss!
Lichen is different from moss . It’s not a plant. It is more of an organism born from a fusional love between an algae and a fungus that live in symbiosis. A lichen is thus only 10% algae against approximately 90% fungi. Algae contain chlorophyll which they use to produce sugars using solar energy, carbon dioxide from the air and water.
These sugars feed the fungi which, in turn, help the algae obtain the quantity of mineral salts and water they need. As we can see, the bark of the trees or shrubs on which the lichen settles is only a simple support, offering little competition to these organisms and sufficient light which is enough to live.
Why are they more numerous in the shade or on the north side?
Because they are less desiccated by the sun, even if they are able to resist a great drought. As soon as the rain returns, the lichens are indeed able to rehydrate in just a few minutes!
Champion all categories, the lichen!
slow growing
The lichen only grows a few millimeters per year. One of the approximately 20,000 species currently listed only grows by a few hundredths of a millimeter per year. Incredible !
Resistance!
Hard to find more resistant than lichen. From the coldest regions of the world to the most suffocating deserts, lichens are present everywhere! Their resistance to climatic conditions is foolproof.
Only one weakness: air pollution!
Reputed to be good indicators of clean air, lichens like the countryside, much less in the city because of the sulfur dioxide pollution from industrial activity that they cannot stand. Although their presence is more and more proven in the heart of large cities. A positive sign…
What to do with lichen on trunks?
Leave him alone! Or, if you don’t find it aesthetic, you can brush the bark to remove it. Do not use a metal brush, it is far too aggressive for the trunk! Prefer a quackgrass brush with softer bristles! But as much prevention, the lichen is not easily removed !