Like the U.S. Air Force, the U.S. Army has now established a desert storage area for old, no longer needed, but not totally useless, equipment. Ever since World War II, the U.S. Army has taken a lot of older equipment it no longer needed and stuck it bone yards. The old equipment, usually trucks, armored vehicles and helicopters, were seen as a potential source of spare parts, or even additional equipment (in wartime, after refurbishment.) The army bone yards were usually near existing army bases, and the equipment quickly deteriorated from the rain, salt (if near the ocean) and changes of season (freezing and thawing). A new army bone yard was established two years ago at the 96,000 acre Sierra Army Depot In the California desert, near the Nevada border. So far, 1,800 vehicles and armored vehicles are stored there, in the dry, salt free air. Many army divisions were disbanded in the 1990s, leaving hundreds of low mileage M-1 tanks, and other armored vehicles, unneeded, but not unwanted if there were a future military emergency. Like the old air force aircraft, the army vehicles sit and deteriorate much more slowly in the desert, waiting for possible activation, and as a source of parts for vehicles no longer manufactured (like the M-1 tank).