Badlands are heavily eroded areas where organic top soil has been washed away. They are nearly completely barren and are a striking feature of volcanic terrane landscape.

In southern Guam, badlands are highly evident in large, bare plots of strikingly red land. They occur throughout all the watersheds. Most of them occur on steeply sloping topography and are continually eroding. The process appears to be so rapid that vegetation cannot naturally recolonize the patches of exposed earth. Studies have indicated that badlands contribute approximately 157 tons/acre/year of soil erosion in a watershed, which is thirty times more than any other land type on Guam.

Badlands develop mostly in areas formerly covered by savanna vegetation. Sadly, this is as a result of human disturbance. The primary cause are fires, many of which are deliberately started to facilitate hunting. Hunters use fire to clear sightlines and draw deer and pigs into the open. Farmers also sometimes illegally burn fields to clear them, and homeowners burn savanna vegetation to create firebreaks around their residence.

The environmental impact of burning extends far beyond the savanna and forested lands. By removing vegetation and leaving bare ground that is susceptible to erosion when it rains, burning severely affects Guam's coastal areas. Large amounts of sediment are washed away and deposited on fringing reefs, where they can kill corals on which they settle.

Consequently, badlands are considered one of the more pressing environmental problems that Guam faces. There are several ongoing projects by federal and local government and organizations directed toward erosion control and badland amelioration.