the lung-shaped lichen of NZ's old beech forest trunks
- Size
- Width: 5–20 cm
- Lifespan
- 20–100 years
- Diet
- Grows on bark of old trees, particularly beech and podocarps, in damp, undisturbed forests. Requires clean air, stable bark surfaces, and high humidity. Sensitive to air pollution, particularly sulphur dioxide and nitrogen compounds.
- Habitat
- Old-growth forests on bark of ancient beech and podocarp trees, where air is clean, moss hangs thick, and humidity remains high from sea level to montane zone.
- Range
- Found in clean-air areas of the South Island beech forests and the North Island volcanic plateau. Most common in damp, undisturbed forests with high rainfall and clean air. Also found in temperate rainforests worldwide.
- Endemism
- Native
- Main Threats
- Air pollution is the primary threat, particularly sulphur dioxide and nitrogen compounds. Also threatened by forest clearance, climate change reducing humidity, and collection by lichen enthusiasts.
- Population
- At Risk – Declining. Sensitive to air pollution, it has disappeared from much of its former range in Europe and North America. Still found in clean-air areas of New Zealand, particularly South Island beech forests and North Island volcanic plateau.
- Conservation Status
- At Risk - Declining
Looks like a lung. Lung lichen has a large, leafy, wrinkled body – pale greenish-grey to brownish-green when dry, bright green when wet. Lobes are broad and rounded, covered in a network of raised, branching ridges and deep, sunken pits. The pattern looks exactly like lung tissue – the bronchial tubes and alveoli, the branching passages of the respiratory system. The lichen that breathes the forest air.
What makes it special is the pattern. One of the most distinctive lichens in New Zealand. The surface is a landscape of ridges and pits, a miniature map of the human lung. The raised ridges are called veins, forming a branching network across the surface. The pits are the depressions between the veins. Together, they create a pattern that is both beautiful and unsettling – a reminder that the forest breathes, that the lichen breathes, that the air connects us all.
A cyanolichen – it contains cyanobacteria (blue-green algae) in addition to green algae. The cyanobacteria give it the ability to fix nitrogen from the atmosphere. A natural fertiliser, adding nitrogen to the forest canopy.
A three-way partnership – a fungus, a green alga, and a cyanobacterium living together. The fungus provides structure and protection. The green alga provides food through photosynthesis. The cyanobacterium provides nitrogen through fixation. A tiny ecosystem on the bark of an old tree.
Grows only on the bark of old trees in clean, undisturbed forests. Sensitive to air pollution, particularly sulphur dioxide from coal burning and nitrogen compounds from car exhaust and farm runoff. In polluted air, it dies. The canary of the forest, the one that tells us whether the air is healthy.
Why is it declining? Air pollution and forest fragmentation. In Europe and North America, it has disappeared from much of its former range. In New Zealand, it is still found in clean-air areas, but under threat from nitrogen deposition, forest clearance, and climate change. The lichen of the old forest, and the old forest is shrinking.
To find lung lichen is to find the lung-shaped patch on the old tree. Large, leafy, wrinkled – a living lung on the bark. Trace the ridges and pits with your finger, feel the pattern, the breathing surface. The lichen of the clean air, the one that looks like lung tissue and breathes the forest.