Picea pungens
Order: Pinales, Conifers
Family: Pinaceae, Pines
Genus: Picea, Spruce
Also known as the Colorado Spruce, the Blue Spruce, or the Silver Spruce.
This classically conical spruce tree is native to the central and southern Rocky Mountains at moderate to high elevations. The common names of the tree come from the silvery blue foliage of young trees and some varieties of the tree. It is well known as an ornamental and is also a popular as a Christmas Tree.
In the wild it often is found in river and stream bottoms in mixed forests of ponderosa pine, Douglas-fir, or white fir. They like wet conditions, but adapt well to dry conditions. They typically grow slowly for the first five years then take off, growing as much as 30 cm a year. If planted in an open field they are susceptible to being blown over in strong winds as they have a shallow root system.
Hardiness: Zones 2-7. (USDA Hardiness Zones)
Identification: Short square needles of about 2-3 cm spaced singly around twigs. Branches and twigs are stiff and held out near horizontally from the tree when young, eventually the branches curve downwards in old age. The cones are 5-10 cm long with light brown papery scales. Sometimes the needle covered galls of a type of adelgid (insect related to aphids) are mistaken for cones. The galls are also at the end of growing branches, rather than held on the underside of branches. The bark is variable from grey to brown, often furrowed into scaly ridges. When mature the tree ranges from 10-35 meters in height depending upon local conditions.
Commercial use is limited since the retention of lower branches leads to a knot filled wood. Additionally it is a light a brittle wood, so it is really only suitable as an ornamental tree or firewood.
Factoids: It is the state tree of both Utah and Colorado. The Latin species name, pungens, means "puncture" referring to the sharpness of the spruce's needles. If you are in the woods and in need of dry twigs to start a fire, check the trunk of larger Colorado Spruces. They often put out small twigs that die back on the main trunk. This is also a way to distinguish it from the very similar Engleman spruce. | 
