The Fourth Cloakwood, also known as Cloakwood Wyverns, is an area in Baldur's Gate. Like the rest of Cloakwood, the player may only discover this area after reaching Chapter 4, and is likewise required to proceed through it to advance the primary story-line. This part of the forest is potentially the most lawless, and thus dangerous. Various Spiders and Wyverns abound, while Gorion's Ward will also likely encounter the unique hostile Hamadryad, along with a few scouting parties made up of Guards - presumably under the employ of the Iron Throne.
The only location of note in the area would be the Wyvern's Cave to the east (4065, 1680); the place a potential companion Coran will mention when encountering him in the First Cloakwood. It's inhabited by two Wyverns and three Baby Wyverns - killing them all will satisfy Coran if he's in the player's party, and allow one to complete the side quest Coran the Wyvern Hunter. Furthermore, one may rest in the Wyvern's Cave, which is interrupted by an adult Wyvern about 90% of the time, for a quick and easy 1,400 exp and a Wyvern Head.