O’er gem-like grass that flashed and glowed The Vánar like a lion strode. Roused by the thunder of his tread, The beasts to shady coverts fled. Tall trees he crushed or hurled aside, And every bird was terrified.

In plain words: Hanuman walks like a lion over the shining grass. His heavy steps scare the animals into hiding, crush trees, and frighten the birds.