Short Description
This conspicuous lichen – also called Tree Lungwort or Lung Lichen – forms broad, lettuce-like patches on the trunks of old trees. In damp forests with pristine air, you’ll see its green lobes hanging from bark or carpeting shaded rocks. The thallus can be extensive (several inches across), bright green when wet and turning grayish when dry, with a surface full of ridges and wrinkles reminiscent of lung tissue. Lobaria pulmonaria is famed as an indicator of healthy, mature forests: it thrives where humidity is high and the air is clean, often in stands of old hardwoods or spruce-fir. Historically, people noticed its lung-like appearance and used it as a folk remedy for respiratory ailments. In the ecosystem, this lichen quietly toils – capturing sunlight with its green algae, fixing nitrogen with its cyanobacteria, and enriching the forest when pieces fall to the ground. Finding a thriving patch of lungwort lichen in the woods is a sign you’re standing in an ancient, unpolluted forest enclave.
TYPE
Lichen
ELEVATION
0–3,500 ft (primarily in lowland to montane forests with high humidity)
HABITAT
Humid, shaded woodlands with mature trees; grows on bark of both hardwoods and conifers (and occasionally mossy boulders) in clean, moist air
BLOOM / SEASON
Non-flowering (lichen; reproduces via powdery soredia year-round, with rare spore-bearing structures)
LEAF & STEM
A foliose (leaf-like) lichen with large, lobed thalli. Each thallus is comprised of broad, overlapping lobes that are 2–5 inches long, irregularly shaped and crinkled. The upper surface is green to olive (bright green when moist), with a network of ridges, folds, and wart-like bumps; the underside is pale whitish to tan, often with fuzzy patches of whitish fungus and some areas harboring blue-green algae (cyanobacteria) visible as darker patches. Rather than discrete leaves, the entire structure is a single lichen body attached at various points to the substrate. It often hangs in floppy sheets or broad scalloped rosettes from bark. Tiny granular structures called soredia (containing both fungus and algae) form along ridges on the surface – these serve as the primary reproductive propagules, rubbing off to start new lichens elsewhere. Apothecia (disk-like spore-producing bodies) are infrequent on lungwort; when present, they appear as small reddish-brown disks on the lichen’s surface, but reproduction is mostly vegetative. The texture of the lichen is pliable and rubbery when damp, but it becomes crisp and brittle when dry.
SIMILAR SPECIES
Other foliose lichens can grow on tree bark, but *Lungwort Lichen* is distinctive for its size and color. *Lobaria quercizans* (Oak Lungwort) and *Lobaria scrobiculata* are related species occasionally found in similar habitats – they also have large green lobes, but are less common and have different surface textures (for instance, L. quercizans has a smoother surface with white patches beneath). More common bark lichens like *Parmelia* (shield lichens) or *Flavoparmelia* are much smaller, forming thinner leafy rosettes just a few inches wide, and lack the thick, corrugated lobes and bright green wet color of Lobaria. One could mistake a patch of lungwort lichen for a moss from a distance (due to its green hue), but up close the lobed, leafy structure and absence of stems makes clear it’s a lichen. Its three-part symbiosis (fungus, green alga, and cyanobacteria) is also unusual – many other lichens have only a two-part partnership.
ECOLOGY
A large foliose epiphyte of humid, old-growth woods (Lobaria pulmonaria) that materially enriches nutrient cycles. Housing both green algae and nitrogen-fixing cyanobacteria in its thallus, it adds bioavailable nitrogen to bark and throughfall, fertilizing the moss–lichen layer and the soil below. Broad, water-holding lobes intercept cloud moisture and moderate bark microclimate while providing forage for gastropods and nest material/camouflage for birds. Extremely sensitive to air pollution, bark desiccation, and canopy fragmentation; healthy mats signal clean air and long forest continuity. Disperses mainly by soredia/isidia, so recovery is slow where populations are lost.
STATUS
Regionally, Lungwort Lichen is an uncommon but significant species. It is not globally rare – it has a broad circumboreal range – but it has declined in areas with air pollution or loss of old-growth habitat. In some parts of Europe it’s become scarce (even legally protected) due to sensitivity to sulfur dioxide and forest clearing. In New England, it persists in pockets of mature forest; in New Hampshire it’s considered an indicator of high-quality woodland but not listed as endangered. As long as clean air and damp, shaded woods are available, this lichen can flourish and even form extensive colonies on favorable trees. Conservation of older forests and good air quality indirectly benefit it. While not at immediate risk in the White Mountains region (where many forests are protected and air is relatively clean), Lungwort Lichen reminds us of the value of intact ecosystems – its presence is a reassuring sign of environmental health. It has no special conservation status here, but its sensitivity makes it a natural barometer of forest air purity and continuity.
Field Notes
- A foliose (leaf-like) lichen with large, lobed thalli. Each thallus is comprised of broad, overlapping lobes that are 2–5 inches long, irregularly shaped and crinkled. The upper surface is green to olive (bright green when moist), with a network of ridges, folds, and wart-like bumps; the underside is pale whitish to tan, often with fuzzy patches of whitish fungus and some areas harboring blue-green algae (cyanobacteria) visible as darker patches. Rather than discrete leaves, the entire structure is a single lichen body attached at various points to the substrate. It often hangs in floppy sheets or broad scalloped rosettes from bark. Tiny granular structures called soredia (containing both fungus and algae) form along ridges on the surface – these serve as the primary reproductive propagules, rubbing off to start new lichens elsewhere. Apothecia (disk-like spore-producing bodies) are infrequent on lungwort; when present, they appear as small reddish-brown disks on the lichen’s surface, but reproduction is mostly vegetative. The texture of the lichen is pliable and rubbery when damp, but it becomes crisp and brittle when dry.
- A large foliose epiphyte of humid, old-growth woods (Lobaria pulmonaria) that materially enriches nutrient cycles. Housing both green algae and nitrogen-fixing cyanobacteria in its thallus, it adds bioavailable nitrogen to bark and throughfall, fertilizing the moss–lichen layer and the soil below. Broad, water-holding lobes intercept cloud moisture and moderate bark microclimate while providing forage for gastropods and nest material/camouflage for birds. Extremely sensitive to air pollution, bark desiccation, and canopy fragmentation; healthy mats signal clean air and long forest continuity. Disperses mainly by soredia/isidia, so recovery is slow where populations are lost.
- Regionally, Lungwort Lichen is an uncommon but significant species. It is not globally rare – it has a broad circumboreal range – but it has declined in areas with air pollution or loss of old-growth habitat. In some parts of Europe it’s become scarce (even legally protected) due to sensitivity to sulfur dioxide and forest clearing. In New England, it persists in pockets of mature forest; in New Hampshire it’s considered an indicator of high-quality woodland but not listed as endangered. As long as clean air and damp, shaded woods are available, this lichen can flourish and even form extensive colonies on favorable trees. Conservation of older forests and good air quality indirectly benefit it. While not at immediate risk in the White Mountains region (where many forests are protected and air is relatively clean), Lungwort Lichen reminds us of the value of intact ecosystems – its presence is a reassuring sign of environmental health. It has no special conservation status here, but its sensitivity makes it a natural barometer of forest air purity and continuity.
Photo Credits
(c) Nathan Sobol / NH48pics.com