This area is one of several areas in the Mammoth Mountain (volcano) area with extremely high levels of carbon dioxide in the soil. The CO2 is contained in the soil and displaces all of the usual atmospheric gases and prevents the roots from absorbing oxygen, killing the plants and trees. The levels of CO2 can be dangerous to visitors if enclosed spaces or low areas are entered or if the vistor, pet, etc., stays too close to the ground playing, sunbathing, etc.