These young people are so sharp that one of them actually shared the point of the story/comparison without the tree. Which is that for the Atonement to cleanse our sins, true repentance must take place which does involve a it of suffering. (Not as much as if we don't repentant!) We can't just say "sorry" and move on. We need to truly be sorry and to recognize the harm of sin, the separation of us from God and who we want to be, godly sorrow leading to change. We must have a broken heart and contrite spirit. Good job!
I found it.
A person who sins is like a tree that bends easily in the wind. On a windy and rainy day, the tree bends so deeply against the ground that the leaves become soiled with mud, like sin. If we focus only on cleaning the leaves, the weakness in the tree that allowed it to bend and soil its leaves may remain. Similarly, a person who is merely sorry to be soiled by sin will sin again in the next high wind. The susceptibility to repetition continues until the tree has been strengthened.
When a person has gone through the process that results in what the scriptures call “a broken heart and a contrite spirit,” the Savior does more than cleanse that person from sin. He gives him or her new strength. That strengthening is essential for us to realize the purpose of the cleansing, which is to return to our Heavenly Father. To be admitted to His presence, we must be more than clean. We must also be changed from a morally weak person who has sinned into a strong person with the spiritual stature to dwell in the presence of God. We must, as the scripture says, become “a saint through the atonement of Christ the Lord” (Mosiah 3:19). This is what the scripture means in its explanation that a person who has repented of his or her sins will forsake them (see D&C 58:43). Forsaking sins is more than resolving not to repeat them. Forsaking involves a fundamental change in the individual.