Sitka Spruce (Picea sitchensis)

Sitka Spruce (Picea sitchensis)
Sitka Spruce (Picea sitchensis)

Robert Potts © California Academy of Sciences

Most of the 30 species of spruce share certain characteristics. Generally the needles are sharp and four-sided, and when crushed release a pungent odor. The woody base of the needle remains on the twig when the needle falls, making the twig feel rough to the touch. The mature cones hang down from the branch, in contrast with the erect cones of a fir. And each of the thin, papery scales making up the cone has two seeds, readily eaten by squirrels, crossbills, and other small mammals and birds.

Spruces are typically tall and conical, but soil and climate may alter their pattern of growth. In Alaska and northern Canada frost, wind and a short growth season stunt the development of Black Spruce; trees more than a hundred years old may measure only 10 feet tall. In the southern Rockies, an Engelmann Spruce may hug the ground, its buds abraded by wind-borne particles. Often associated in people's minds with northern forests, spruces penetrate south along mountain slopes. Two of the seven species native to North America—the Engelmann Spruce and the Blue Spruce (Picea pungens)—almost reach the Mexican border. (the Blue spruce is also widely planted as an ornamental.)

Sitka Spruce (Picea sitchensis)
Sitka Spruce (Picea sitchensis)

Charles Webber © California Academy of Sciences

On eastern mountains the Red Spruce (Picea rubens) extends south to the Carolinas.

Alaska's state tree, Sitka Spruce thrives in the coastal regions of Southcentral and Southeast Alaska. The tree's lumber is strong and lightweight, making it ideal for construction in aircraft, gliders and boats. It is also popular as a tonewood for guitar bodies. Commercially, Sitka Spruce has been the most valuable species. With a usual height of 160 feet, Sitka Spruce is the largest spruce in the world.

Needles of Sitka Spruce are flattened, bright yellow-green, sharp-tipped. Cones are flexible, with wavy edges on scales. Bark is reddish brown, loose, scaly. Branches are drooping.