What does Esperanza say is the reason for the existence of trees in The House on Mango Street?

In the vignette entitled "Four Skinny Trees," Esperanza compares herself to the trees on Mango Street. She says that the trees understand her because they are skinny like she is. These trees were planted by the city as if they were trying to beautify the area, but they seem forgotten like so many people who live there. Esperanza appreciates trees because they are strong. These four trees specifically are survivors because they "grab the earth between their hairy toes and bite the sky with violent teeth and never quit their anger. This is how they keep" (74). When she uses the word "keep," she means they survive.

Esperanza says that trees exist as examples for living, existing, and surviving. Not only that, but trees teach her to attack life with strength no matter where she is planted. Every time she is sad, she looks at the trees and sees that they "grew despite concrete" (75). This means that even though the trees aren't in a forest, and they are surrounded by concrete rather than dirt, they persevere and fight for their existence. She also says that these trees never forget to reach for what they need and want, so she uses them to remind her to do the same in her own life.