CHEYENNE, Wyo. (AP) — An outbreak of spruce beetles continues to accelerate across hundreds of square miles of new forest in Colorado, although a much larger outbreak of the similar mountain pine beetle continues to slow across Wyoming, Colorado and the Black Hills, according to a new survey by the U.S. Forest Service. Every year, the Forest Service conducts an aerial survey of forests in Colorado, Wyoming and South Dakota. The 2013 survey shows spruce beetles spreading to ever-larger expanses of new forest in Colorado for a fifth consecutive year. The spruce beetle infestation remains small compared with the havoc wreaked by the mountain pine beetle. Spruce beetles have infested and substantially killed about 2,700 square miles of Wyoming and Colorado forest since the mid-1990s, but that's still only about one-fourth the scope of the mountain pine beetle outbreak. Spruce beetles haven't been a major problem in the Black Hills. In Wyoming, they've killed large numbers of trees in the Medicine Bow and Sierra Madre ranges in the southern part of the state and remain active in the Absaroka Mountains southeast of Yellowstone.