The fungus, _Fomes pini_, is the cause of a heartrot of widespread
distribution. Common names for the rot produced by this fungus are: red
heart, red ring rot, or white peck. The disease is commonly associated
with mature and over-mature conifers, especially Douglas fir, larch,
spruce, and pine. In the southern United States, the fungus attacks all
species of mature pine.
[Illustration: Fruiting body of redheart on southern pine.]
Generally, infection of all hosts occurs through dead branch stubs.
Early stages of decay caused by _F. pini_ are characterized by a
discoloration of the heartwood, often appearing light red to reddish
brown. The advanced stages of heartrot appear as elongated white pockets
or flecks, formed parallel to the grain and separated by apparently firm
wood. Often the pockets become resin filled. On southern pine hosts, the
conks are often bracket-like or hoof-shaped. The upper surface appears
dull grey to dark brown, with concentric furrows parallel to the margin
of the fruiting body. The lower side is a light brown to brownish gold,
rimmed by a velvety golden brown margin. Swollen knots result from the
living wood tissue trying to overgrow the knot where a conk is forming.
[Illustration: Cross section of infected tree showing rotted and
decayed heart wood.]
In southern forest stands, heartrot damage may be reduced by harvesting
mature pines prior to the age of extreme susceptibility to fungus
attack. Some degree of shade tree protection can be obtained by pruning
dead and dying branches flush with the main stem. This will allow the
knot to be quickly overgrown by sap wood, preventing the heartrot fungus
from entering through the branch stub.