SB 6.4.7
na drumebhyo maha-bhaga
dinebhyo drogdhum arhatha
vivardhayisavo yuyam
prajanam patayah smrtah
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
O greatly fortunate ones, you should not kill these poor trees by burning them to ashes. Your duty is to wish the citizens [prajas] all prosperity and to act as their protectors.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
It is indicated herein that the government or king has the duty of protecting not only the human beings, but all other living entities, including animals, trees and plants. No living entity should be killed unnecessarily.