Olympic Habitat Development Study
US FOREST SERVICE

 

Station 1 -
Sitka Spruce
(Picea sitchensis)
Family Pinaceae

This northwest tree is the largest of the world’s spruces and can be one of the most prominent species in forests along the western coast of North America. It has very prickly needles, stout twigs, drooping branchlets, 6-8 cm2-3 inches papery cones with thin wavy cone scales, and distinctive bark which breaks up into small gray or reddish-brown scales.  Trees can be large -- commonly up to 70 m230 feet tall and 2 m6.5 feet in diameter with the largest trees 4 to 5 m13 to 16 feet in diameter. Sitka spruce can be very long-lived with some trees reported to be 700 or 800 years old.

Sitka spruce is less shade tolerant than some of its tree associates such as western hemlock and western redcedar but more shade tolerant than Douglas-fir or western hemlock.   It is found primarily in coastal forests from southeast Alaska to northern California.  Spruce seeds will germinate in dark forests but the seedlings will not survive.  Thinning and the creation of gaps will favor spruce seedlings over those of western hemlock, one of its most common tree associates.

Sitka spruce is one of the few conifers which can “rebuild” crown by adding epicormic branches.(Branches which sprout from suppressed buds under the bark on the trunk or branches of trees) Thinning can stimulate the development of these branches, especially when there are major changes in light along the portion of the stem without branches.  Gaps in a forest canopy stimulate both the development of epicormic branches and the growth and retention of existing lateral branches.

Since elk avoid the prickly spruce seedlings and preferentially browse other more palatable species, elk can be unexpected benefactors for Sitka spruce seedlings by increasing the percentage of spruce seedlings which survive in comparison to seedlings of other trees.

It’s strong, but relatively light wood made spruce a very popular material for airplanes during the early days of aviation.  It is a common belief that Howard Hughes’ “Spruce Goose”, --the largest flying boat ever built—was made out of the wood of this tree, but actually it was mostly made out of birch.   Spruce wood is widely used to make paper and valued for specialty uses such as high-quality pianos and other musical instruments.  Other special uses include: oaks, spars, and masts for boats and blades for wind turbines.  Northwest natives used its fibrous, strong root bark to make water-tight baskets and hats as well as rope.


 

Epicormic branches can form on Sitka spruce.  These can be short-lived small branches or develop into large branches which will survive for decades or even centuries.
Bark detail and some epicormic branches on Sitka spruce. Epicormic branches can form on Sitka spruce.  These can be short-lived small branches or develop into large branches which will survive for decades or even centuries. Large diameter branches close to the ground indicate this spruce had few neighbors when the branches formed.
Epicormic branches can form on Sitka spruce. These can be short-lived small branches or develop into large branches which will survive for decades or even centuries.