Evaluating Decay and Holes in an Old Oak Tree

What You’re Seeing

The holes likely come from woodpeckers or squirrels excavating in wood already softened by decay fungi. The living tissue is just under the bark; the interior dead wood can decay for decades without killing the tree.

Risk Assessment

• If the canopy is full and no large limbs are falling, the tree is stable for now.
• Watch for upper limb breakage during storms—decay at branch attachments is a warning sign.
• Do not fill the holes; they drain naturally and filling traps moisture.

Health Maintenance

Fertilize with 10-10-10 at 1 lb per inch of trunk diameter in fall or early spring to boost vigor and compartmentalization.