Chihuahua Spruce (Picea chihuahuana) is a medium-sized evergreen tree growing to 25-35 m tall, and with a trunk diameter of up to 1 m. It is native to northwest Mexico, where it occurs in 25 small populations in the Sierra Madre Occidental mountains in Chihuahua and Durango. It grows at moderate altitudes from 2300-3200 m, growing along streamsides in mountain valleys, where moisture levels in the soil are greater than the otherwise low rainfall in the...