Picea engelmannii, also known as Engelmann spruce, is a species of coniferous tree that is native to western North America. It is commonly found in high-altitude areas such as the Rocky Mountains and is often used for lumber, paper, and Christmas trees. Some synonyms for Picea engelmannii include the blue spruce, Colorado spruce, and silver spruce. These names are based on the tree's appearance, as it has bluish-green needles and a silvery bark. Additionally, it is sometimes referred to as the mountain spruce or alpine spruce because of the high-altitude habitats in which it grows.