Which tree species is known to have included bark as a risk factor for limb failure?

The Bradford pear is well-known for its unique growth habit, which can lead to structural weaknesses, particularly including bark. This species has a tendency to develop included bark at the forked branches due to the way the tree grows. Included bark occurs when two branches grow closely together, causing their bark to become trapped between them instead of forming a strong joint as they mature. This can compromise the integrity of the limb connection and increases the likelihood of limb failure, especially during high winds or heavy snow loads.

The other species listed have different growth characteristics and risks associated with them. While all trees can have structural issues, the Bradford pear's susceptibility to included bark is particularly notable and a key reason why it is frequently discussed in the context of limb failure risks.