This painting is part of a series, based on an oak tree that actually stands firm in the Lower Galilee.  The angle of the tree and its many branches are in a way symbolic of the firm stature of the Jewish People, who have survived almost every trial and tribulation (to put it lightly!) Actually, there is a verse in Isaiah 6:13, "...As an terebinth or an oak, whose trunk remains even when it casts its leave, so shall the holy seed be a trunk [for the newborn Jewish people.]"