At some point during the life of this roof, there was a leak, most likely from the old ridge vent. The leak rotted out a section of the wood. That section was cut out and replaced. The shingles in this area were also replaced.

The ridge vent along with the house and at both dormers was replaced with a GAF ridge vent. The ridge cap shingles were then laid on top. This new ridge vent and shingles will prevent leaks and should no longer have rotting wood.