Content
- Lichen indicate health of the fruit tree
- What are lichens?
- Damage lichen the fruit tree?
- When and how should lichens be removed?
- Tips
Lichen usually does not harm fruit trees
Lichen indicate health of the fruit tree
Especially old fruit trees and other deciduous trees are often densely overgrown with lichens. Many a gardener suspects that these organisms harm their wood. But is it really like that?
What are lichens?
Lichen are not independent plants, but a living community of mushroom and alga. Both form a symbiosis in which they support each other. Mushrooms are able to extract water and nutrients from the soil or air, while algae produce nutrients through photosynthesis. In this way, the two organisms condition and feed each other. There are around 2019 different species, which can assume a very different appearance, and the color spectrum varies greatly. Lichen can rest loosely on its ground, but some species are also overgrown with it.
Damage lichen the fruit tree?
As lichens grow mainly on weakened and old trees, many gardeners suspect they are causing significant damage. This is not true, as lichens feed themselves autarkic and are not dependent on the fruit tree as a food source. They filter their nutrients from the air and not from the pathways of the affected tree. Also, the growth of the bark does not hinder these organisms, because they do not penetrate to the Cambrian - where the bark is formed - due to missing roots. However, their presence is often a sign that the tree is not feeling well: lichens prefer to colonize already weakened trees, as they no longer provide enough defense material. This is especially true for trees that are deficient in nutrients or that are too dark.
When and how should lichens be removed?
A fighting of lichens is not necessary. What you can do, however, is to improve conditions for your infested tree. This can be done by loosening the soil and fertilizer or by converting to a sunnier location. If the tree is heavily overgrown with lichens and frequently struggles with recurring pest infestation, removal may nevertheless make sense: Some pathogens and pests like to hide in the organisms. However, the lichens can only be scoured off with vigorous scrubbing with a hard brush - chemical agents are not approved for domestic use.
Tips
Lichens are considered pointer plants for a healthy, clean air: Since the organisms have no excretory organs, they are very sensitive to pollutants from the air. Ergo, you can be glad to find lichen-covered trees in your garden: it simply means that literally the air is clean.