Whatever stops growing, dies. Plants are alive, bugs are alive, animals are alive, humans are alive, and if any one of these stops growing, it dies. Plants wither just like bodies decay.
When you remove a head of lettuce from its life source, cut into it so that it’s leaves bleed milk, and you consume it, it is the same as doing so to an animal.
Scientists took two identical plants, and put them in two different rooms. To one they talked to it everyday. They spoke in loving tones, and played soft classical music. It thrived. To the other plant they spoke insults in angry but not loud tones, and played heavy metal music. It died.
With all the dead trees there are, I can’t believe someone don’t believe that plants die.