What is a fir tree?

Oregon tree names keep people guessing

By Judy Scott

Douglas-fir cones have pitchfork-shaped bracts that are longer than the scales.

Many people are aware that despite its name, Douglas-fir is not a true fir. It's also not a pine, not a spruce and not a hemlock. Outside of the United States, it is often called Oregon pine, also a misnomer.

What is a Douglas-fir, then?

It's a unique species, in a class by itself, according to the newly revised Oregon State University publication, "Understanding Names of Oregon Trees," (EC 1502).

The publication is available only online at http://bit.ly/OSUESec1502 .

"It's little wonder that people are confused by tree names," said author Scott Leavengood, director of the Oregon Wood Innovation Center at OSU. "Foresters often name trees by physical appearance, while the wood products industry may name trees based on characteristics of the wood. Botanists name trees based on anatomical characteristics and evolutionary relationships to other trees."

The publication outlines quirky naming devices. For example, you can usually distinguish a "true tree" if its names are not hyphenated or run together. For example Atlas cedar is a "true cedar" whereas western redcedar and Port-Orford-cedar are "false cedars."

Scientists use Latin names to avoid confusion. The first word in the scientific name refers to the genus and the second is the species. "Trees in the same genus are closely related and have similar characteristics," Leavengood said. Trees of the same species can be interbred.

"If you want to know if a tree is a fir, pine, cedar or other type of tree, check the genus name," Leavengood suggested. "For example, unless a tree is in the genus Abies, it is not a true fir, and unless a tree is in the genus Cedrus, it is not a true cedar."

Oregon does have six native, true firs: White fir, California red fir, Grand fir, Pacific silver fir, Noble fir and Subalpine fir.

Check out the OSU publication for more information on Oregon trees, such as cedars, western juniper, mountain-mahoganies, poplar and myrtlewood.

Also available from OSU is a full-color field guide, "Trees to Know in Oregon" (EC1450), in the OSU Extension online catalog: http://bit.ly/TreesToKnow. This 60th anniversary edition includes more than 70 new color photos and costs $18.

Douglas-fir

Douglas-fir is not a true fir, but what is it? We could devote several pages to this tree alone. Douglas-fir is a unique species that has given botanists fits. Over the years, botanists have called Douglas-fir a pine, a spruce, a hemlock, and a true fir. The wood products industry often calls the wood of young trees red fir and the wood of older trees yellow fir. The Japanese call it Oregon pine.Douglas-fir’s scientific name is Pseudotsuga menziesii.

Pseudotsuga (pronounced soo-doe soo-ga) means “false hemlock,” so at least we know it’s not a hemlock!The needles of Douglas-fir and true firs look similar,

so in some ways, Douglas-fir resembles true firs. Botanically speaking, one reason Douglas-fir cannot be classified as a true fir is the difference in its cones. True fir cones stand upright on their twigs and disintegrate in the wind rather than falling to the ground. By comparison, Douglas-fir cones are unique in appearance (figure 2), hang down from the branches, and usually fall to the ground intact.In summary, Douglas-fir is not a pine, not a spruce, not a hemlock, and not a true fir—it’s in a class by itself!

This is a Douglas-fir. Notice how the cone hangs down from the branch and has pitchfork-shaped bracts.