When it comes to describing an area that is covered with a large number of trees, several synonyms can be used instead of the phrase "most tree-covered." Words like "wooded," "forested," and "treed" effectively convey the sense of a dense forest or woodland. Other synonyms include "sylvan," "arboreal," and "foliated." Another term that can be used is "timbered," which often implies that the area has been or is being exploited for lumber. It is crucial to choose the right synonym to fit the context and tone of the writing, as each word may evoke a slightly different image in the reader's mind.