"Dense vegetation" refers to an area or place with a lot of plants growing very close together, making it difficult to see or move through them easily. Full definition
When researchers finally arrived, they found solitary animals, high up in the forest canopy, screened from the ground by dense vegetation, and seldom descending. (newscientist.com)
Approximately one - half the island is covered with dense vegetation. (massaudubon.org)
They camouflage themselves in dense vegetation at the canopy of trees preventing easy discovery. (palawan.ph)