When we observe the trees and plants around us, we find that even the plants of the same species bear different sizes and shapes. In fact no two trees are alike even if they are growing near one another. This is the result of the intense competition and many traits that trees have to face and acquire.
Every tree tries to reproduce to propagate its lineage. For this it produces seeds. But this is not the end of the story. The seeds have to be broadcast away from the tree preferably to a place where the parent tree does not have its influence over the resources required for growth. To scatter the seeds the tree shall in ideal case try to grow very tall and branches at the top.
Now take its another trait. Every tree has to harvest the sun energy. For optimal absorption of the energy the tree shall desire to have the design in which branches shall be horizontal and non-overlapping. This way every leaf will act as a energy cell.
Third trait is mechanical stability. For this the tree shall want minimum horizontal branches because the branches shall try to destabilize it.
Now as the saying goes no one gets the complete world. The foremost truth about the life is compromise. So when all the traits compete simultaneously there is compromise. The mixing ratios of the traits is the result of the helplessness of the tree. This behavior has been called “Frustration Principle” by biologist Karl Niklas. Niklas used computer models in which he kept the two traits constant and varied the third one. The results were as expected but when he mixed the traits in different ratios the final shape of the tree was like we see in reality around us.
This can be compared to smart cellphones which have a camera also. Although camera does good work but it cannot replace the stand alone camera. Similarly we have gadgets which can do many jobs but they are good for picnics where it is not the refinement but collection of many tools which come as handy but are not as perfect in quality as the individual tool shall be. But then who wants to take a lots of tools for picnic?