Good day with the coming of the windy season it is always good to assess your trees for their structure and stability most people concentration on the roots system looking for soil or root movement but other stress,es can also occur such as Torsion which is the twisting of the tree and its branches causing branch failure or shear stress in the trunk (see photo) Torsional stress occurs when a branch/trunk or root twists leading to maximum stress near the perimeter. trees with asymmetrical crown or branches with asymmetrical foliage distribution may experience an uneven wind load, resulting in higher levels or torsion, recently exposed trees can also experience torsion stress that they are not normally exposed to high levels of wind this could be because they have had trees or building recently removed or in the sample in the photo the tree may have grown above other trees or structures. Torsion has not received a great deal of attention in tree mechanics, it is likely a significant factor, especially in branch failure