Prescribed burns are fires intentionally lit to burn off vegetation under controlled conditions. (they are also known as controlled burns sometimes) Most natural areas have evolved with fire, and if they do not see periodic fire they accumulate fuel until a catastrophic fire occurs. Prescribed burns can be used to prevent fuel buildup, encourage native plant growth, and improve grazing land and hydrology. Used skillfully they are an important tool in ecosystem management. However, they have become somewhat of a controversy as of late as a badly managed fire in Los Alamos raged out of control and destroyed much of the town. Many people used this to argue against prescribed burns, but in reality it is in a sense an argument for prescribed burns.. if fires had been allowed to burn at their natural, small state, the fuel buildup which caused this fire would never have happened. Now the key to prescribed burns is somehow mitigating the excess fuels to avoid such disasters from recurring