Health Protection, Southern Region
caused by Hericium erinaceus, Pleurotus sapidus, Polyporus fissilis, and Laetiporus sulphureus
Importance. - Heart rot is the single most important disease of merchantable, hardwood timber in the South. Heart rot can affect
all parts of the tree, but frequently occurs in the butt log, where its impact on the value of the tree is greatest.
Identifying the Fungi. - Many fungi are responsible for heart rot in hardwoods; however, four species cause about half the
damage. These are H. erinaceus, P. sapidus, P. fissilis, and L. sulphureus. These and other fungi
can be identified by the conks they produce.
Identifying the Injury. - Damage resulting from most heart rots can be easily observed. Most begins at basal injuries, like
those caused by fire and logging damage. In addition, poorly healed and decayed branch stubs and other stem defects are strong indications of heart rot.
Heart rot developing on oak sprouts. (Click for detail. JPG 48K).
Basal heart rot on oak. (Click for detail. 43K).
Biology. - Heart rots begin through wounds, if the wounds are sufficiently deep or large. Healing is slow and permits a succession
of chemical changes, and bacterial and fungal colonization. If the succession is complete, decay will be initiated and will continue for many years.
Control. - Once the decay process begins, there is no control. Consequently, prevention through the reduction of wounds
from all agents is crucial to controlling heart rot. Affected trees that have any merchantable volume should be salvaged, while those that do not
should be felled or girdled.