It does not inhabit the east coast. The Rimu Bracket avoids dry forests. It avoids the rain shadow of the Southern Alps. Look for it on the western slopes. The West Coast. Fiordland. The damp, heavy air of the Hokitika Valley. The bracket is large. Thick. The size of a dinner plate. Sometimes larger. The upper surface is white when young. It ages to cream, then buff, then pale brown. The margin is thick. Rounded. The underside has pores. Tiny. White. The bracket is soft when young. You can dent it with a thumb. Mature specimens harden. They become woody. They persist for years. Some outlive the trees they killed. Range across New Zealand is fragmented and western. Strongholds exist in Westland, Fiordland, and the western Nelson region. Populations also occur in the North Island's central plateau, the Tararua Ranges, and the western slopes of the Ruahine Range. The species does not occur in eastern South Island. Not in Canterbury. Not in Otago. Not in Marlborough. The climate is wrong. Too dry. Too variable. Rimu grows in Canterbury. The bracket does not follow. It needs the constant moisture of western forests. The fog. The daily rain. The humidity that never drops below seventy percent. Without these conditions, the bracket fruits poorly. It may not fruit at all. The mycelium survives. The bracket stays hidden. Threats are historical and ongoing. Rimu logging removed most mature rimu from accessible forests between 1920 and 1980. The bracket needs old trees. Trees with heart rot. Trees with wounds. Logging targeted the largest individuals. The same individuals the bracket colonised. The fungus survived in remnant stands. In Westland, where logging was less intensive. In steep valleys where extraction was impossible. The second threat is the shift to plantation forestry. Pine replaces rimu. The bracket does not grow on pine. It does not grow on exotic trees. Its host is gone. The fungus retreats. The third threat is climate drying. Western forests are getting drier. The brackets fruit less frequently. The mycelium waits. It waits for rain. The rain comes less often. Habitat is mature lowland rimu forest. Not regenerating rimu. Not rimu in mixed forest. The species prefers stands where rimu dominates. Dacrycarpus dacrydioides (kahikatea) and Prumnopitys ferruginea (miro) can host it. Rarely. The bracket grows on the trunk. At the base. On exposed roots. It enters through wounds. Wind snap. Possum damage. Old branch stubs. The infection spreads upward. The tree rots from the inside. Hollows form. Birds nest in them. Kaka. Kakariki. The tree falls. The bracket continues on the log. It fruits for a decade. The log sinks into the forest floor. The bracket subsides. The fungus moves to the next tree. Diet is parasitic then saprotrophic. Rigidoporus ulmarius causes a white rot in rimu heartwood. It digests lignin and cellulose. The wood becomes pale. Spongy. Light. A cubic metre of infected rimu weighs half what it should. The bracket absorbs nutrients. The tree starves. The leaves thin. The crown dies back. The tree lives for years. Decades. It becomes a standing dead trunk. The bracket fruits annually. New pores form each summer. The old pore layers build up. The bracket thickens. It becomes a record. Each layer a year. Each year closer to the tree's collapse.