Betula lenta canker
Grafton Land Trust
Grafton MA
5/26/09
Side view of canker on Black Birch.
Guillaume Ayotte Cote says that is most likely caused by Inonotus glomeratus.
Front view. About 8" wide.
Broke of about an inch cube to see what it
looks on the inside. NOT Chaga!
The fungus that causes this canker also produces a true fertile fruiting body.
In that way it is further similar to Inonotus obliquus.
Inonotus glomeratus
Formerly Polyporus glomeratus,
this fungus causes a relatively common canker rot on sugar maple. It
reportedly is the most important decay fungus of sugar maple in Ontario,
accounting for up to 40 percent of volume losses. It also is found on red maple
and beech.Branch stubs and wounds are the primary entry points for
infection. Once the decay is advanced in the stem, the fungus produces a
sterile, thick mass of tissue that spreads over the wound area or around the
branch stub. This soon turns black, crusty, and cracked. The canker is
irregularly shaped and generally becomes elongate with raised margins. Canker
rots produce fertile fruiting bodies or conks only after the tree dies. Canker
rots cannot be eliminated from the forest, but maintaining healthy and
wound-free trees and removing infected ones should reduce the incidence of these
diseases.