Emotional wounds stem from our insecurities and fear; created by our experiences and strengthen by our traumas. In situations where we face or deal with actions that cause us extreme distress, we are inevitably scarred by them and will always remember them. Similarly, trees represent this idea as well. A "perfect" tree comes with no flaws or issues, but no tree is perfect and thus they are bound to be marred with scars. Every scar made on a tree as it grows is like a scar we feel as we grow. These scars are deep at first, and as time goes on, those scars get lighter and lighter but never truly disappear. A mark on a tree made from a seemingly insignificant thing may seem tiny but can never be erased.
I wrote this quickly so you may need to change stuff
The poet warns the people who glorify the oppressor by reminding them that no score is settled till that which is true and right prevails. The oppressors may think they have won, but an unjust cause is always overturned as a hopeful morning rises after a dark night fro the oppressed. 3
Swan's lightbulb didn't last as long as Edison's and required more current to operate at the same power level as Edison's. Higher current meant you need thicker wire to power it.