Question

central idea on killing a tree​

Answer 1

pour tree poision on the roots

Answer 2

If it’s the poem you seem to address ;

Any harm done to the nature due selfishness by human beings is simply unpardonable. The trees provides natural habitat for numerous animals, living creatures and helps to protect the surrounding environment to the required stature.
But man believes in being very self-centred and fail to realise that forests and its richness actually are lifesavers for human existence.