Velvet roll-rim

Velvet roll-rim (Tapinella atrotomentosa) is a well-known fungus that acts as a wood-decay agent in forest environments. While often studied by mycologists for its morphological features, in the context of forest pathology, it is recognized as a cause of destructive brown rot, primarily affecting coniferous stumps and weakened live trees.

The pathogen spreads through its mycelial network, which colonizes the woody substrate. It causes a specific type of brown rot, characterized by the enzymatic degradation of cellulose while leaving the lignin mostly intact. This process is typical for saprotrophic fungi that can transition into opportunistic pathogens when host trees are under environmental stress.

The primary hosts of this fungus are coniferous trees such as Scots pine (Pinus sylvestris) and Norway spruce (Picea abies). The development of the fungus is highly dependent on humidity levels and the availability of woody debris. Moist forest soils provide ideal conditions for the colonization of deadwood and the subsequent production of basidiocarps.

Signs of infestation include the presence of large, velvety, dark-brown mushrooms at the base of trees or on stumps. Internally, the wood undergoes structural changes; it becomes dark, brittle, and breaks into cubical chunks upon mechanical pressure, which is a classic symptom of advanced brown heart rot.

• Regular forest sanitation and removal of deadwood.
• Stump removal in managed plantations to break the infection cycle.
• Protection of live trees from wounding and soil compaction.
• Maintaining proper forest stand density to reduce tree physiological stress.

The economic impact of the velvet roll-rim is associated with the loss of wood quality and the degradation of timber assets. Protection and prevention strategies are focused on minimizing the accumulation of substrate and improving overall forest hygiene to inhibit the widespread establishment of the fungal colonies.