As the father and mother are the friends and maintainers of their children, as the eyelid is the protector of the eye, as the husband is the maintainer and protector of a woman, as the householder is the maintainer and protector of beggars, and as the learned is the friend of the ignorant, so the king is the protector and giver of life to all his subjects. The trees are also subjects of the king. Therefore they should be given protection.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
तोकानां पितरौ बन्धू दृशः पक्ष्म स्त्रियाः पतिः । पतिः प्रजानां भिक्षूणां गृह्यज्ञानां बुधः सुहृत्
tokānāṃ pitarau bandhū dṛśaḥ pakṣma striyāḥ patiḥ | patiḥ prajānāṃ bhikṣūṇāṃ gṛhyajñānāṃ budhaḥ suhṛt
SB 6.4.12