Srimad Bhagavatham : 6. 4. 8.
Chapter-4. ( The Hamsa-guhya Prayers )
Slokam : 8.
aho prajapati-patir bhagavan harir avyayah,
vanaspatin osadhis ca sasarjorjam isam vibhuh.
Because He is the all-pervading and indestructible master, He has created all these trees and vegetables as eatables for other living entities.
Soma, the predominating deity of the moon, reminded the Pracetas that this vegetation had been created by the Lord of lords to provide food for everyone.
If the Pracetas tried to kill them off, their own subjects would also suffer, for trees are also required for food.