Lungwort Lichen (Lobaria pulmonaria)
The Lungwort lichen is one of the most iconic and recognizable lichens in the Scandinavian forest. Beyond its striking appearance, it serves as a vital indicator species, signaling the presence of ancient, ecologically rich forest environments.
Characteristics
The Lungwort is a large foliose (leaf-like) lichen that can occasionally reach up to one meter in diameter.
Appearance: It has deeply lobed, angular edges. The upper surface features a distinct reticulate pattern of ridges and depressions, resembling lung tissue (hence its name).
Color: When wet, the thallus is a vibrant, bright green. When dry, it turns brown or greyish-brown.
Underside: The underside is light brown and finely woolly (tomentose), interspersed with pale, naked spots.
Reproduction: It is often sterile, but under favorable conditions, it can produce red to reddish-brown apothecia (fruiting bodies). Small grains (soralia) or finger-like outgrowths (isidia) often appear along the ridges for vegetative reproduction.
Biology: It contains green algae but also harbors cyanobacteria in specific pockets, allowing it to fix nitrogen from the air.
Confusing Species: It can be mistaken for Lobaria scrobiculata, but that species is blue-grey when wet and has more rounded lobes.
Note: Sometimes black, disk-like spots appear on the lichen. These are not part of the lichen itself but a parasitic fungus called Plectocarpon lichenum.
Ecology
This species thrives on the trunks of various deciduous trees in areas with high, consistent air humidity and semi-open light conditions.
Southern/Central Sweden: Found mainly on noble broad-leaved trees (oak, beech), aspen, and old pollarded trees in meadows or pastures.
Northern Sweden: Commonly grows on goat willow (sälg), aspen, and rowan, and occasionally on rock faces.
Habitat: It is most abundant in late-successional forests, particularly those rich in old deciduous trees following historical forest fires, as well as in swamp forests and on cliffs.
Distribution
While found from Skåne to the far north, its distribution is uneven.
Hotspots: It is most frequent in the high-precipitation areas of western and southwestern Sweden, as well as the coastal and inland regions of Norrland.
Global Status: It is widely distributed across moist, temperate regions of the Northern Hemisphere. While still relatively common in Norway and parts of Finland, it is very rare in Denmark and is declining rapidly across much of Europe.
History: Once described as common in older literature, it has seen a massive decline over the last 100 years due to modern forestry.