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.

Tuesday, June 23, 2015

Focus on Grand Fir

Grand fir is the only true fir found in the lower elevations of the Pacific Northwest, so it’s no surprise that it’s sometimes called “lowland fir.” David Douglas was more impressed when he found large specimens growing near the Columbia River on one of his journeys to the Northwest and named it grand fir, Abies grandis. It deserves this grander name. It can grow to 200 feet tall.

Needles: Grand fir is easy to identify just by looking at its needles. They spread out on opposite sides of the twig in flattened rows, unlike any other conifer in the Northwest. 
However, you may notice that when growing in direct sunlight the needles sometimes crowd to the top of the twig. Each twig typically has a mixture of long and short needles, the longer ones being about 1.5 inches. The individual needles are flat with a groove along the top. Their color is a dark, shiny green on top with two white lines underneath. Pacific silver fir, which grows at mid to higher elevations of the Cascades has similar needles but they point forward and upward rather than lying flat like grand fir. However, if you find a twig blown out of the top of a grand fir, it can look very much like it came from a Pacific silver fir.

Note the non-flat needles
Cones: You can hike the forests of the Northwest for years and never see a grand fir cone. They sit upright on the branches near the treetop and are difficult for ground-dwelling humans to see. Like other firs, grand fir cones fall apart at maturity, dispersing the winged seeds and leaving a cone core spike on the branch. You won't find grand fir cones on the ground unless they were dropped by a squirrel, which happens more often than you might think.

Bark: The gray bark is smooth with blisters on small branches, breaking into flat ridges and narrow furrows on large trees. It is easily distinguished from the deeply furrowed bark of Douglas fir or the stringy western red cedar bark, but looks similar to the bark of western hemlock.

Grand fir grows at lower elevations throughout most of western Oregon and Washington, but it also grows at elevations up to 5000 feet. It is the only true fir you will find growing below 1500 feet. (Remember, Douglas fir is not a true fir.) Grand fir is a moderately shade-tolerant tree that thrives in moist areas. It is not as abundant as Western Hemlock in its range, but you can usually find it growing here and there among the other conifers, often under larger Douglas fir. Grand fir is more common in the mountains of northern Idaho, occasionally growing in pure stands.

The grand firs that grow east of the summit of the Cascades are sometimes characterized as a separate variety. These eastern trees grow significantly slower than the west slope trees.

Like other true firs, grand fir is used to make plywood and paper. It is also one of the species of lumber sold as “Hem-Fir,” indicating that it is either hemlock or fir. It is not as strong as Douglas fir lumber, but is used in home construction for framing. The white, soft wood is easy to work with and does not split when nailed, which makes it an ideal choice for baseboards and other mouldings. Christmas tree lots often feature grand fir. Its dark-green needles and its strong fir-like fragrance make it a popular choice. If you are allergic to the strong fragrance, you might consider it for outside planting, and choose a similar-looking Nordmann fir for a Christmas tree.

The biggest grand firs grow in western Washington. The largest by volume is in Olympic National Park.  The tallest is 267 feet in height. It’s located in the Glacier Peak Wilderness in the North Cascades.

Looking for grand fir in the Cascades near Crater Lake and the coastal mountains of southwest Oregon can be tricky. Grand fir in these areas hybridizes with white fir (Abies concolor). The characteristics of the hybrids can vary between these two species.

See also

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