Maple with Northern Tooth Fungus: Long-Term Decay, Plant a Successor

A maple has heart rot from northern tooth fungus (Climacodon septentrionalis)—hollowing in a main trunk. Crown looks good. Owner wants to plant a replacement now.

Understanding the Fungus

Decay fungi enter through bark wounds. They digest dead heartwood, not living sapwood. The tree can live many decades with a hollow trunk if the crown remains healthy.

Management

• Fertilize with 10-10-10 at 1 lb per inch trunk diameter to boost vigor.
• No treatment for the fungus itself.
• Plant a new maple nearby—it will mature by the time the old one fails. The fungus won't spread to the new tree unless it's wounded.

Enjoy the old tree while it lasts; decay is slow and structural failure usually requires a storm.