Pine heart rot fungus

The pine heart rot fungus (Phellinus pini) belongs to the kingdom Fungi, phylum Basidiomycota. It is a perennial wood-decay fungus that causes central red-brown heart rot in coniferous trees.

The fruiting bodies of the fungus are hoof-shaped or resupinate, very hard, and woody. The upper surface is typically dark brown or nearly black, deeply furrowed, and cracked.

The context (flesh) of the fruiting body is rusty-brown and firm. The lower surface (hymenophore) is covered with pores that are round in young specimens and become labyrinthine with age.

Fungal spores are dispersed by the wind and infect trees primarily through broken branches, bark wounds, frost cracks, or insect damage sites.

Biologically, this fungus is an active decomposer of lignin and cellulose, leading to the gradual internal structural degradation of the tree trunk.

The primary hosts of Phellinus pini are conifers, especially Scots pine, although it can also infect spruce, cedar, and larch.

The infection targets mature and overmature stands, causing significant economic losses to the forestry industry due to the degradation of timber quality.

The fungus develops in the heartwood of the trunk, causing deep internal rot that can extend vertically for several meters.

As a result of the fungal activity, the tree loses its structural integrity, leading to windthrow and stem breakage during strong gusts of wind.

Young trees are affected by this pathogen significantly less often, as the fungus requires a well-developed heartwood section for active colonization.

An external indicator of infection is the emergence of characteristic fungal fruiting bodies on the trunk, usually located at the sites of dead or broken branches.

In the early stages, the heart rot can be identified during log inspection or by sounding the trunk, which produces a dull thud in the affected areas.

Infected wood takes on a specific red-brown coloration, becomes brittle, and delaminates, sometimes showing white fibrous mycelial mats.

The presence of hidden infection is often indicated by "top-dying," which manifests as premature yellowing and shedding of needles in the upper canopy.

Resin flow at the attachment points of the fungal fruiting bodies is also a typical sign of an active pathological process within the trunk.

The main control measure is the timely sanitary felling of infected trees to prevent the spread of spores to healthy specimens.

It is essential to conduct regular forest pathology surveys to detect infected trees during the early stages of fungal development.

Avoiding mechanical damage to bark and trunks during forestry operations is crucial to closing entry points for the infection.

Maintaining optimal stand density and conducting timely thinning operations contribute to increasing the overall resistance of the stand to pathogens.

In forest nurseries and park areas, the application of protective sealing compounds to the cut surfaces of large branches is recommended to prevent spore inoculation.