-- This fungus is distributed widely on oak, elm, and maple species
in the East. It is common at the bases of older, living oaks in yards,
parks, and along streets. While its ability to kill trees is questionable,
it will decrease tree health over time.
Fungus. -- Fruiting bodies are tan- to buff-colored conks or irregular
cushions, 4 to 24 inches by 3 to 10 inches, on roots or at bases of
trees. Young conks may grow around green leaves or show leaf imprints
on top from where leaves lay on the growing conks. A yellowish liquid
may exude from young conks, and old conks look like burned wood on top
Injury. -- Thinning crowns may result from long-term infections
that degrade root systems. The slow crown deterioration weakens the
tree and may lead to a more serious butt rot.
-- Microscopic spores enter the tree through dead or scarred roots or
through fire or logging scars at tree bases. Once extensive decay has
occurred, conks are produced.
-- The best control is to prevent injury (e.g., from lawn mowers and
tire traffic) because the fungus enters through wounds in the bark of
roots or tree bases. As with all root and butt rotters, bole and crown
conditions should be monitored regularly for signs of weakening and