Lichens consist of two different plantlike organisms, an alga and a fungus. They live in symbiosis with each other, with the fungus being the most visible.
Lichens consist of two different plants, green algae (Chlorophyta) or blue-green algae (cyanobacteria) and a fungus (fungi). They live in symbiosis with each other, with the fungus being the most visible. Lichens grow on stones, old walls and trees. Lichens do not take food or water from their hosts. They live on light and moisture (rain or absorbed from the air).
Lichens are often yellow, grey, orange or brown. Lichens grow very slowly, tolerate drought and can grow very old.
Lichens prefer slow-growers among shrubs and trees; lichens are more likely to be found on walnut and apple trees than on true fast-growers, such as poplars. Lichens are sensitive to climate change and air pollution. The lichen species Parmelia is common on fruit trees.
Where to find
- Are commonly found
- Fruit trees (apple tree, walnut tree)
Control
Lichens are harmless; action is not necessary.
Prevention
Does not apply. If lichens are undesirable, plant the affected trees and shrubs in a sunny spot and prune the trees and shrubs so that the wind has free rein.
