Tokyo Ghoul Facts/News And Everything You Didn't Know [And Theories]

7

So about the parasol tree in 5 
Parasol tree in Chinese is Aogiri

The poem

On a high tower I lean on a slender breeze
My vision ends in spring and sorrow
Rising dark and dark at the Sky's edge
Grass colored by misty light of dying sun
No words. Who can understand me?
Why I stand at this banister
Maybe, I should go drunk,
Singing over my cup
But, forced joy is tasteless
I don't regret losing my belt and robe
I'm losing my self

(Let's break it down shall we?)

On a high tower I lean on a slender breeze

The high tower represents the the torture chamber, it means he had escaped.

My vision ends in spring and sorrow
Rising dark and dark at the Sky's edge

Kaneki realizes that the way here perceived life was wrong
"Rather than hurting others be the person who gets hurt"
That it wasn't okay that it ended up his mothers death and him facing a lot of suffering he had to endure.

Grass colored by misty light of dying sun

Part of Kaneki's name has the meaning Sun and golden meaning he is dying of his old self or the human in him has been killed

No words. Who can understand me?
Why I stand at this banister

No one not even himself can understand why he had gone through this much.

Maybe, I should go drunk,
Singing over my cup

Maybe he should give in to insanity thus turning him into a real ghoul and killing other ghouls in the process and eating them while before he couldn't even look at a dead body.

But, forced joy is tasteless

He doesn't enjoy doing this being that he has been forced to do

I don't regret losing my belt and robe

He doesn't regret becoming strong by the wrong means. That he was able protect his loved ones until the near end.

He's losing himself ,he is getting away from others.