This is a blog about the native conifers of the Pacific Northwest. It is a companion to the Northwest Conifers site. The blog will focus on timely and interesting details about our conifers, their connections to the rest of the environment, and our connection to them.

Sunday, August 26, 2018

Focus on Spruce

Sitka spruce at the
Cape Perpetua

About 30 species of spruce grow across the northern hemisphere, most notably in the cold arctic regions. Fossils of spruce date to 65 million years ago. The spruces are most closely related to the pines, but you would never guess this from looking at any spruce. Judging from the needles and cones, you would think that they’re not even in the same family. Three species of spruce are native to the Pacific Northwest: Sitka spruce, Engelmann spruce, and Brewer spruce. The most ancient species were two of our natives: Brewer spruce and Sitka spruce. Also, spruces originated in the Northwest. Millions of years before humans discovered the Bering Land Bridge, spruces made a slow migration across to reach Asia and Europe. It may seem odd to think of trees migrating. They generally stay rooted in one spot. Yet even though the trees themselves don’t travel, their winged seeds do. So each generation can sprout a few hundred feet beyond the previous generation. It’s easy to see that trees would be able to migrate thousands of miles in millions of years.

Spruces can grow to 200 feet tall, given a chance. Sitka spruce is the largest species of spruce. The largest Sitka spruce in Oregon is located at Cape Meres. The largest Sitka spruces in the world are in Washington state, the Lake Quinault Spruce, growing on the south shore of Lake Quinault, and the Queets Spruce, growing near the Queets River in Olympic National Park.
Spruce needles and cones

Twig with pegs where needles attached
The Spruces are easy to identify. They have some distinguished and distinguishing features. First, consider the needles: They look like Douglas fir needles, radiating all around the twig, but they are pointed and sharp. Unlike Douglas fir and the true firs, each spruce needle grows on a small peg. In fact, these pegs are unique in the pine family, and remain even after a twig loses its needles. The cones have thin scales, with their bracts hidden safely inside on mature cones, again unlike Douglas fir, which has conspicuous three-pointed bracts poking out from each scale. The bark is gray and usually breaks into scales on large trees.

Spruce gall
Spruce trees often develop galls. People often confuse these galls with cones, especially when there are no cones present on the tree. These galls are caused by the gall adelgid, a tiny insect that loves to eat the tender spruce needles after they burst from buds in the spring. The tree reacts by producing a gall on the twig tip.

The scientific name for spruce is Picea, which is derived from the Latin for "pitch."

Spruces dominate vast northern regions of the northern hemisphere including Alaska, Canada, and Russia. The only other conifers that grow this far north are the larches. Farther south in North America and Asia, spruces are confined to higher elevations in the mountains, extending into Mexico in North America and to the Himalayas in Asia. Sitka spruce is one exception to this attraction to cold extremes. It clings to the Pacific Coast from California to Alaska, thriving where other trees avoid windswept shorelines continuously peppered with salty ocean spray.

Engelmann spruce bark
Spruce wood is used for construction and making paper. The original Christmas tree was a Norway spruce. The most celebrated use of spruce is in the making of fine string instruments. It’s also used for piano sound boards. You might think of Howard Hughes’ famous Spruce Goose airplane as another use of spruce wood. The huge airplane was made of wood, but the wood used in the Spruce Goose was birch. No wonder Howard Hughes never liked that name. It’s also been called the Flying Lumberyard, but I doubt that he would have liked that any better. The Spruce Goose is now on display at the Evergreen Aviation & Space Museum in McMinnville, Oregon.

Conifers of the World, James Eckenwalder