Bark inclusions in the root system

Bark included between main roots (see arrow in photo) can be a source of weakness. Roots with inclusions are not as well connected to each other as roots without inclusions.
Treatment: It is not clear what to do with this one. You might slow the growth on one of the roots by removing a side root from it. Perhaps consider reducing or thinning the canopy regularly to reduce likelihood of failure in storms on important trees.