Heart-rot is not a disease: reframing wood decay in living trees

When fungi are seen fruiting on tree trunks, branches and twigs, they are often automatically thought to be causing disease. Likewise, the hollowing of dead woody tissue in the centre of trunks is often instantly thought of as harmful. Yet there is a wide diversity of tree-fungus interactions, and the majority of those involving wood decay fungi do not have negative consequences for the tree. This biologically inaccurate framing of wood decay fungi in general, and heart-rot in particular, has major consequences for research priorities, forest management, and public perceptions of fungi-tree interactions. Heart-rot has important ecological functions, to the extent that research to accelerate heart-rot is ongoing. We must actively reframe the narrative more precisely to represent the actual role of heart-rot as a functional component of tree and forest systems because the logical consequence of describing heart-rot as disease is that valuable trees and the species they support will be lost.