the dark hair lichen hanging from NZ's subalpine trees
- Size
- Length: 5–20 cm
- Lifespan
- 10–50 years
- Diet
- Grows on branches and trunks of trees in damp, undisturbed forests. Requires clean air, stable bark surfaces, and high humidity. Sensitive to air pollution and bark disturbance. Prefers old-growth forest with stable microclimate.
- Habitat
- Hangs from branches of trees in damp, undisturbed forests. Forms dark brown to blackish-brown, wiry, bristly strands.
- Range
- Found throughout the North and South Islands in damp, undisturbed forests. Most common in the South Island's beech forests and the North Island's western ranges. Also found in temperate and cold regions worldwide.
- Endemism
- Native
- Main Threats
- None significant. This species is common and widespread in clean-air areas. Localised threats include forest clearance, air pollution, and climate change reducing forest floor humidity.
- Population
- Not Threatened. This is a common and widespread lichen in New Zealand, particularly in the South Island's beech forests and the North Island's western ranges. It grows on the branches and trunks of native and introduced trees.
- Conservation Status
- Not Threatened
The one that looks like a tangle of dark wires has a body that is dark brown to blackish-brown, with long, wiry strands that hang from the branches like a tangled mess of bristles. The strands are thin and stiff, often reaching 5 to 15 centimetres in length. They are branching and intertwining, forming a dense, dark curtain on the branches. It is the lichen of the wrong colour, the one that looks like something went slightly wrong, the one that seems out of place in the bright green forest.
What makes it special is the colour. The bristle lichen is one of the darkest lichens in New Zealand. Its strands are dark brown to blackish-brown, almost black in some light. It stands out against the pale bark of the trees, a dark stain on the branch. Unlike the pale greenish-grey of most fruticose lichens, the bristle lichen is dark, brooding, slightly ominous. It is the lichen of the dark forest, the one that looks like it belongs in a haunted wood, the one that makes the forest feel older and stranger.
The strands are stiff and brittle, not flexible like Usnea. They snap when bent, with a clean break. The surface is rough and bristly, covered in tiny, hair-like projections. The bristles give the lichen its name and its texture. Under a hand lens, the bristles are visible, tiny spikes covering the surface of the strand.
Biologically, the bristle lichen is a partnership, a fungus and an alga living together. The fungus provides structure and protection. The alga provides food through photosynthesis. The dark colour is an adaptation to cold climates, absorbing more heat from the sun and protecting the alga from freezing.
The bristle lichen is also a bioindicator. It is sensitive to air pollution, particularly sulphur dioxide. In polluted air, it dies. It is the canary of the canopy, the one that tells us whether the air is healthy, the one that disappears when we poison the sky.
To find bristle lichen is to find the dark tangle on the branch. It is dark, wiry, and bristly, a living mess on the tree. You can run your fingers through the strands and feel the stiff, bristly texture. It is the lichen of the dark bristle, the one that looks like something went slightly wrong, the one that proves that even the darkest things can be beautiful in their own way.