frost fungus that silvered alpine slopes

Size
Width: 30–50 cm
Lifespan
5–10 years
Diet
Saprotrophic – fed on frost-shattered logs, dead standing trees, and fallen timber in mountain beech forests. A bracket fungus built for the cold – thick, woody, with a varnished cap that gleamed like polished mahogany. Grew slowly, year after year, adding a new layer of spore-bearing pores each season.
Habitat
Mountain beech forests of the Southern Alps and volcanic slopes of the central North Island. A bracket fungus built for the cold – thick, woody, with a varnished cap that gleamed like polished mahogany. Grew slowly, year after year, adding a new layer of spore-bearing pores each season. The recycler of the alpine forest.
Range
Found in mountain beech forests of the Southern Alps and volcanic slopes of the central North Island, notably in Nelson and Otago. Described from early naturalist accounts and preserved specimens collected in the late 19th century. Last reliably recorded in the 1890s.
Endemism
Endemic
Main Threats
Logging of mountain forests was the primary threat. Also threatened by the removal of dead timber and the loss of frost-damaged logs it needed to colonise. Last reliably recorded in the 1890s. A few specimens remain in museum collections – their varnished caps still gleaming, their mountain forests logged decades ago.
Population
A true giant among bracket fungi, related to the living reishi mushroom (Ganoderma lucidum) and other woody polypores. Estimated cap width 30–50 centimetres, significantly larger than the largest living Ganoderma species (20–30 centimetres). Last reliably recorded in the 1890s, gone by the 1910s.
Conservation Status
Extinct
Bracket fungi are those woody, shelf-like growths that sprout from dead or dying trees, hard as leather, lasting for years. They are the recyclers of the forest, the slow ones, the fungi that take their time. And there was once a bracket fungus that grew larger than any alive today – a woody shelf 50 centimetres across, its cap varnished and gleaming like dark mahogany, its underside covered in millions of tiny pores releasing clouds of brown spores. It grew on the frost-damaged logs of the mountain beech forests, breaking down the wood that winter had killed. It was the giant frost fungus, and it is gone. Size and cold tolerance made it special. A 50-centimetre bracket fungus is a spectacular thing – a woody shelf that could weigh several kilograms, attached to the side of a fallen log like a shield. Its cap was thick and hard, with a shiny, varnished surface that protected it from rain and snow. Its underside was a pale, creamy surface covered in thousands of tiny pores – the openings of the tubes where its spores were produced. It decomposed the frost-damaged timber. In the mountain forests, winter frost kills branches and whole trees. The dead wood lies on the forest floor, waiting to be recycled. The giant frost fungus was one of the few fungi that could colonise this wood, breaking down the tough lignin and cellulose. Its mycelium spread through the log, digesting it from the inside, turning dead wood into nutrients for the forest. Its woody bracket could persist for years, even decades, adding new layers of spore-producing tissue each season. A large specimen might be 50 years old or more. It reproduced by spores, released from the pores on its underside. The spores were brown, dust-like, carried by the wind. When they landed on suitable dead wood – preferably beech or other mountain trees – they germinated, sending out hyphae that colonised the timber. That strategy works when the forest is intact and the dead wood is abundant. It fails when the forest is logged and the frost-damaged logs are removed. Logging and the removal of dead timber destroyed it. When Europeans arrived, they logged the mountain beech forests for timber. They took the living trees – and they also took the dead ones, clearing the forest floor of fallen logs. The giant frost fungus, which needed large, frost-damaged logs to grow, lost its habitat. Without a steady supply of dead timber, the fungus could not reproduce. Its old brackets fell from the remaining logs, crumbling to dust. No new brackets appeared. By the 1910s, it was gone. The last specimens were probably collected by a naturalist who had no idea he was holding the final individual. He dried them, put them in a drawer. And the mountain forest fell silent. The smaller bracket fungi survived. Ganoderma lucidum and its relatives still grow on dead wood in forests around the world – smaller, less spectacular, but alive. But New Zealand's giant frost fungus is extinct – a ghost of the alpine forest, a woody shelf that no longer gleams on the fallen logs. We logged its forest. We cleared its logs. Then we wondered why the mountain felt so empty.