The Hanged Man in the Tarot is one of the spookier-looking cards. But it's not really about someone hanging on or from a tree, it's symbolic of a more profound message. Oh the crazies we create when we take these things literally. Anyhoo, this symbolic image is about sacrifice. It's about finding peace, a need to find peace. And to find peace, we have to "sacrifice" (release) that which is not making us feel so peaceful. Most notably, fear. Also anger (which is often just a front for fear).
So why a man hanging from a tree? Well, it's just trying to convey a situation where there's nothing this person can do in this moment to change his situation. And it's a Catch 22. Because if he doesn't find peace with this situation, it's not apt to change. Because when the heart is filled with fear, it's like a caged lion. Fear blocks our power, and we need our power to change things for the better. Peace is where our power opens up and flows. It's transformational.
We "rise from the dead" when we cleanse the heart of fear, and instead fill it with peace...light-heartedness, playfulness, acceptance of "what is" in this moment. Not hating, fearing or being angry about hanging from a tree (although ya' gotta allow yourself to feel it, bring it up from the depths, become aware of it, before healing and peace will happen).
It's another reason for "gratitude," because it helps fill the heart with empowering peace, love and joy.
The only real chains on us, the only cage, the only imprisonment is holding on to fear. The only true freedom is letting it go. Peace opens the flood gates to our power. That's why it's necessary for those who wish to control us to keep us in fear. Much more difficult to control a lion outside of its cage, yes? ;-)