AVOIDING COMPETITION. “Currently three avoidance responses to this situation have been observed. (1) New branches grow away from the direction of higher FR/R. (2) The whole plant moves away as in the Stilt Palm by differential growth of prop roots toward the light. (3) Apical dominance is increased, the main stem elongates more quickly with longer spaces between leaves which are larger in surface area with longer petioles and fewer more vertically erect branches.”
http://link.springer.com/article/10.1007/s00114-005-0014-9