In life, we are given trials. We can either be stricken down by them or become strong and grow because of them them. The poem talks about how people, like trees, grow and reach their true potential by overcoming adversity. It is through struggles, like a tree fighting through forest growth, to reach the sun, that we grow and discover our true potential.
The tree that never had to fight
   For sun and sky and air and light,
But stood out in the open plain
   And always got its share of rain,
Never became a forest king
   But lived and died a scrubby thing.
The man who never had to toil
   To gain and farm his patch of soil,
Who never had to win his share
   Of sun and sky and light and air,
Never became a manly man
   But lived and died as he began.
Good timber does not grow with ease,
   The stronger wind, the stronger trees,
The further sky, the greater length,
   The more the storm, the more the strength.
By sun and cold, by rain and snow,
   In trees and men good timbers grow.
Where thickest lies the forest growth
   We find the patriarchs of both.
And they hold counsel with the stars
   Whose broken branches show the scars
Of many winds and much of strife.
   This is the common law of life.