You see how, in the winter storms, the trees yield that save even their twigs, but those who oppose it are destroyed root and branch.Please explain.

The statement is a metaphor used to establish superiority of a humble and flexible approach as compared to a egoistic and rigid approach in dealing with opposition from others, and with adverse circumstances. When strong wind blows the trees and other plants that are flexible bend under the pressure exerted by the wind. This reduces the total force to which they are exposed. As a result even small twigs on the trees do not break away from the tree. However, trees that are rigid, and this generally includes the bigger trees, do not bend under the pressure of the strong winds. This show their strength. But in spite of this strength, such trees are more likely to be completed uprooted by the strong winds.

In this way the bending of trees is presented as a symbol of flexibility and humility, while remaining upright of big trees is presented as a symbol of rigidity and pride, and in this way the metaphor is used to highlight the benefits of humility and flexibility as a way of dealing with others and with the circumstances.