Question

How dies someone who plant a tree plant ' the flag of breezes free'

Answer 1

The tree planter does gain heavenly joy and a sense of satisfaction by planting the tree. As he  knows that he is helping his fellow human beings as well as future generations by planting a tree, it brings a greater sense of accomplishment. This is the thing what motivates him to plant the tree. Moreover, he also enjoys the green beauty, the songs of the birds living of the tree, the cool shade and all that in his lifetime.

Answer 2

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a person who plants a tree plants the flag of breezes free.the poet is trying to compare the plant and the flag ,the plants leaf flutters so smoothly in the wind like a flag which flutters in the air.