Black Spots on Cut Birch Branches: Harmless Decay Fungi

The raised black areas on your cut white birch branches are fruiting bodies of wood-decay fungi. They colonize dead wood when warmth and moisture allow. Indoors, low humidity halts their growth completely.

No Action Needed

• Scrubbing removes bark, not the fungus inside.
• Bring branches inside—the black spots won't spread or harm anything.
• If aesthetics bother you, cut fresh branches and move them indoors promptly.

These fungi pose zero risk to your home or health. They're simply nature's recyclers doing their job on dead wood.