He hung himself because he didn’t want to “shame the earth goddess.” The Igbo community and the entirety of the Umuofian society considered suicide to be one of the worst commitable crimes ever. To kill oneself while touching the ground was considered disrespectful to the earth gods and therefore he hung himself from the trees.
Hope this helped. The book is pretty good, if you have any more questions on it let me know since I just finished reading this for an AP class.
