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.

Saturday, December 30, 2017

Pacific Silver Fir

Pacific silver fir at Hoyt Arboretum

Pacific silver fir is a high-elevation tree that can reach a height of 200 feet (60 meters). At the timberline where winters are cold and the snow is deep, silver fir grows closer to the ground where the snow can protect it from the wind and cold. If you venture there in the winter, you will notice that the dark green needles look nearly black in the winter whiteness.

Although it is generally easy to identify our native conifers, the firs can be tricky. However, Pacific silver fir isn’t closely related to other native firs and doesn’t hybridize with any of them. It is easy to distinguish this fir from other high-elevation firs by its needles and unique bark. 

Pacific silver fir has needles similar to grand fir, dark green on top with white lines underneath.  But the needles point forward and upward rather than lying flat like grand fir needles. However, both of these trees have a mischievous habit of impersonating the other. Grand fir needles growing in direct sunlight will often point upward. And silver fir needles growing in deep shade will often lie flat like grand fir needles. Look for branches growing in moderate shade to distinguish the species. It’s easy to distinguish Pacific silver fir from subalpine fir and noble fir. They both have white lines on both the upper and lower sides of the needles.

Young bark is gray and smooth with resin blisters. Older bark breaks into gray, scaly plates. These large irregular plates are unique to Pacific silver fir, distinguishing it from the furrowed bark on other native firs.

The cones sit upright on the branch and turn from green to purple. Like other firs, the cones fall apart at maturity, leaving a cone core spike on the branch. Pacific silver cones are much larger than grand fir or subalpine fir, but much smaller than noble fir. The immature pollen cones look like delicious tiny raspberries, but certainly are not edible. 

Pollen cones

Pacific silver fir grows at higher elevations in the Cascades, the Olympic Mountains, and a few locations in the Coast Range in Oregon and Washington. On the Olympic Peninsula and north to southeast Alaska, it grows down to sea level. It often grows in pure stands of large trees and sometimes near the timberline, mixed with subalpine fir and mountain hemlock.

Like grand fir, Pacific silver fir is more shade tolerant than our other native firs. You can find it growing in the understory in stands of towering mountain hemlock, for example, on the trail between Mount Hood Meadows and the Timberline Trail. Pure stands of Pacific silver fir grow in the Badger Creek Wilderness near Flag Point on the Tygh Creek Trail. 

Native people used the boughs for floor bedding, chewed the pitch as gum, and used the wood for firewood. Like hemlock and most other firs, the wood is not generally regarded as high quality. Construction lumber from these trees is sold as “hem-fir.” It’s not as strong as Douglas fir, but it has some honorable uses. Many moldings are made from these species. The wood is soft, doesn’t split when nailed, and stains nicely. More commonly these trees are made into plywood, perhaps an acceptable fate, or suffer the final indignity of being made into paper.

The common name reflects the color of the lower surface of the needles and the silvery bark. The scientific name is Abies amabilis. Scottish botanist David Douglas named it Picea amabilis when he found it growing near the Columbia River. It was later classified as Abies, but kept its species name, amabilis, which means "lovely." Other common names: White fir, red fir, lovely fir, amabilis fir, and Cascades fir.

Unless you like snowy winter sports, you won’t see any Pacific silver fir until next summer. But if you can’t wait, you can see some planted just west of the Visitor Center at Hoyt Arboretum in Portland.