Since a poem can have different meaning for different
readers and the poet can mean two different things using the same imagery, both these meanings can be justified in . context of the poem:
1. Yes, the poem presents a conflict between man and nature. Man has always caused much harm to nature, without realizing that it actually is a harm to the human race. Humans cut down forests for forest goods, which has destroyed a lot of natural beauty. By keeping trees inside walls and denying them their natural home, they are denying them their freedom. That is why, the trees want to move out. Similarly, in the poem A Tiger in the Zoo, the poet shows that animals feel bounded by cages and they want to get free and run wild in the open.
2. If trees have been used as a metaphor for human beings, then the poem would mean that like the trees, humans too want to break free of the boundaries that life puts on them. Modern life with all kinds of physical comfort has also brought a lot of moral downfall. Our lives have become busy and we have become selfish and greedy. Man would also want to enjoy the beauty of nature and go out in the open and be free, just like trees.