What does the author contemplate while visiting the Epping Forest in the nonfiction book, Underland?

The M25 motorway encircles the Epping Forest, and it is never more than two and a half miles wide, making it a decidedly non-wild forest, although it is still easy to get lost in, MacFarlane says. The Epping Forest is the site of MacFarlane's contemplation of the wood wide web, or the millions of tiny connections between living things at or below the surface in the forest. This setting allows MacFarlane to discuss the understory and the underworld of the forest without going to a remote location, thereby showing that such connections exist almost everywhere.